web-based calculator for residential energy …€¦ · the potential upgrades considered were:...
TRANSCRIPT
WEB-BASED CALCULATOR FOR RESIDENTIAL ENERGY
CONSERVATION
by
Pulkit Gupta
A thesis submitted in conformity with the requirements
for the degree of Masters of Applied Science
Graduate Department of Chemical Engineering and Applied Chemistry
University of Toronto
© Copyright by Pulkit Gupta 2009
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Abstract
Thesis Title: Web-Based Calculator for Residential Energy Conservation
Author: Pulkit Gupta
Degree: Masters of Applied Science
Year of Graduation: 2009
Department: Graduate Department of Chemical Engineering and Applied Chemistry
University: University of Toronto
A large Canadian financial services institution (FSI) is planning to develop a web-based
application aimed at helping homeowners calculate the financial and environmental impacts of
potential energy conserving upgrades to their dwellings. The algorithm for this calculator, the
questions to be posed to the homeowners, and how the homeowners can access some of the
scientifically-inclined energy-related information is presented. The potential upgrades
considered were: furnace efficiency, heat-pump efficiency, programmable thermostats,
window-efficiency, building insulation, lighting efficiency, and refrigerator efficiency. The
algorithm developed was used to demonstrate that changing just one of the input variables
can, in certain cases, have a drastic effect on the resulting output: upgrades with positive net
present values (NPV) can drop to negative NPV, and in certain cases CO2 emissions can
increase as a result of the upgrade considered. The effect of future changes in fuel prices, and
the price levied on CO2 emissions is also demonstrated.
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Acknowledgement
I would like to acknowledge the extraordinary support I received from Professor Joseph C.
Paradi in completing this research. I am truly indebted to him for all the help and knowledge
he provided throughout the preparation of my thesis.
I would also like to thank Professor Yuri Lawryshyn and the generous people at the FSI:
Sandra O., Andrew C., Aleks L., Jim H., Brett B., and Gord K. for providing the opportunity to
work on a very real-world and very interesting project. They have helped me grow and learn
along numerous avenues.
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Table of Contents
ABSTRACT.................................................................................................................II ACKNOWLEDGEMENT................................................................................................ III TABLE OF CONTENTS................................................................................................. IV LIST OF FIGURES ....................................................................................................... V LIST OF TABLES........................................................................................................VI CHAPTER 1 INTRODUCTION......................................................................................... 1
1.1 MOTIVATION ................................................................................................... 1 1.2 PROBLEM DEFINITION......................................................................................... 2
CHAPTER 2 BACKGROUND ........................................................................................... 3 2.1 REVIEW OF ACADEMIC LITERATURE ......................................................................... 3 2.2 ENERGY SAVING TECHNOLOGIES ............................................................................ 7 2.3 OTHER EXISTING CALCULATORS........................................................................... 26 2.4 CO2 EMISSIONS ............................................................................................. 39 2.5 INCENTIVE PROGRAMS IN CANADA ........................................................................ 42 2.6 NET PRESENT VALUE ........................................................................................ 46
CHAPTER 3 FINANCIAL & ENVIRONMENTAL IMPLICATION OF ENERGY SAVINGS................ 51 3.1 UPGRADING FURNACE EFFICIENCY ........................................................................ 54 3.2 UPGRADING HEAT PUMP EFFICIENCY...................................................................... 60 3.3 UPGRADING TO A PROGRAMMABLE THERMOSTAT ........................................................ 65 3.4 INCREASING BUILDING ENVELOPE INSULATION.......................................................... 69 3.5 UPGRADING WINDOW EFFICIENCY ........................................................................ 74 3.6 UPGRADING LIGHTING EFFICIENCY........................................................................ 82 3.7 UPGRADING REFRIGERATOR EFFICIENCY.................................................................. 88
CHAPTER 4 CALCULATOR MAIN MODULE ..................................................................... 97 CHAPTER 5 RESULTS AND DISCUSSION .....................................................................101
5.1 IMPACT OF CHANGING A SINGLE VARIABLE...............................................................101 5.2 EFFECTS OF FUTURE REGULATORY AND MARKET CHANGES .............................................113
CHAPTER 6 CONCLUSIONS .......................................................................................118 GLOSSARY OF ACRONYMS & TERMS...........................................................................119 REFERENCES & BIBLIOGRAPHY .................................................................................121
REFERENCES ..........................................................................................................121 BIBLIOGRAPHY ........................................................................................................123
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List of Figures FIGURE 2-1 A TYPICAL NATURAL GAS FIRED FURNACE ................................................................. 8 FIGURE 2-2 A TYPICAL HEAT PUMP AVAILABLE ON THE MARKET ..................................................... 10 FIGURE 2-3 IMAGE OF A PROGRAMMABLE THERMOSTAT (LEFT) AND A NON-PROGRAMMABLE ONE (RIGHT) .... 13 FIGURE 2-4 INSTALLING A NEW PROGRAMMABLE THERMOSTAT ..................................................... 14 FIGURE 2-5 POSITION OF WALL INSULATION AND ATTIC INSULATION.............................................. 16 FIGURE 2-6 PICTURE OF SINGLE (LEFT), DOUBLE (MIDDLE), AND TRIPLE (RIGHT) GLAZED WINDOWS........ 18 FIGURE 2-7 IMAGE ON A TYPICAL ILB (LEFT) AND CFLB (RIGHT) ................................................. 21 FIGURE 2-8 SAMPLE ENERGUIDE LABEL FOR A REFRIGERATOR ..................................................... 24 FIGURE 2-9 FIRST SET OF INPUTS FOR MANITOBA HYDRO’S CALCULATOR........................................ 29 FIGURE 2-10 DETAILED INPUT FOR MANITOBA HYDRO’S CALCULATOR............................................ 30 FIGURE 2-11 OUTPUT REPORT FROM MANITOBA HYDRO’S CALCULATOR .......................................... 32 FIGURE 2-12 FIRST SCREEN OF THE HOME ENERGY SAVER - LBNL CALCULATOR................................ 33 FIGURE 2-13 SECOND SCREEN OF THE HOME ENERGY SAVER - LBNL CALCULATOR............................. 34 FIGURE 2-14 SCREEN FOR DETAILED INPUT FOR WATER HEATER ................................................... 35 FIGURE 2-15 SCREEN SHOWING FINAL UPGRADE RECOMMENDATIONS............................................. 36 FIGURE 2-16 CASH FLOW DIAGRAM................................................................................... 47 FIGURE 2-17 CONSUMER PRICE INDICES FOR CANADA FROM 1961 TO 2007 ................................... 48 FIGURE 5-1 NET PRESENT VALUE RESULTS FOR CHANGING NATURAL GAS PRICES ...............................114 FIGURE 5-2 NET PRESENT VALUE RESULTS FOR CHANGING ELECTRICITY PRICES ................................115 FIGURE 5-3 NET PRESENT VALUES FOR SIMULTANEOUS CHANGES IN ELECTRICITY & NATURAL GAS PRICES ..116 FIGURE 5-4 NET PRESENT VALUE RESULTS FOR CHANGING CO2 EMISSION PRICES..............................117
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List of Tables TABLE 2-1 FURNACE PRICES .............................................................................................. 9 TABLE 2-2 HEAT PUMP PRICES.......................................................................................... 11 TABLE 2-3 PRICE SURVEY OF COMMERCIALLY AVAILABLE PROGRAMMABLE THERMOSTATS ....................... 15 TABLE 2-4 PRICE SURVEY OF BUILDING ENVELOPE INSULATION .................................................... 17 TABLE 2-5 PRICE SURVEY OF WINDOWS (INCLUDING INSTALLATION COST)....................................... 18 TABLE 2-6 PRICE SURVEY OF COMMERCIALLY AVAILABLE CFLBS ................................................... 22 TABLE 2-7 PRICE SURVEY OF NEW REFRIGERATORS .................................................................. 25 TABLE 2-8 LIST OF OTHER EXISTING CALCULATORS................................................................. 26 TABLE 2-9 VALUE DELIVERED BY CALCULATORS JUDGED AGAINST THE CRITERIA LISTED BELOW ............... 28 TABLE 2-10 CO2 EMISSION FACTORS.................................................................................. 41 TABLE 2-11 FEDERAL GOVERNMENT GRANTS AND INCENTIVE PROGRAMS – ECOENERGY RETROFIT .......... 44 TABLE 2-12 PROVINCIAL GRANTS AND INCENTIVE PROGRAMS ...................................................... 45 TABLE 3-1 TYPICAL ENERGY PRICES BY PROVINCES .................................................................. 52 TABLE 3-2 CO2 EMISSION FOR ELECTRICITY BY PROVINCES......................................................... 52 TABLE 3-3 AVERAGE LIFE EXPECTANCY OF EQUIPMENTS ............................................................. 53 TABLE 3-4 SHIPMENT WEIGHTED AFUE FOR HEATING SYSTEMS BY YEAR OF SHIPMENT ......................... 58 TABLE 3-5 LOOKUP TABLE FOR FS, KPF, TI – TO USING SGI, ORIENTATION, AND CITY AS INPUT.............. 76 TABLE 3-6 SHIPMENT WEIGHTED ENERGY FACTORS (EF) FOR REFRIGERATORS................................... 89 TABLE 3-7 MAXIMUM ANNUAL ENERGY CONSUMPTION LIMITS FOR REFRIGERATORS .............................. 90 TABLE 4-1 MATRIX OF QUESTIONS ..................................................................................... 98 TABLE 5-1 INPUTS FOR 6 CASES TO STUDY EFFECTS OF REGULATORY AND MARKET CHANGES .................113
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Chapter 1 Introduction
1.1 Motivation Climate change has been a popular for a number of years. Recently, however, the rise in
crude oil prices has catalyzed Governments, Industry and the average citizen to do everything
possible to conserve energy. If the trend of increasing fuel prices continues, energy-efficiency
is sure to continue to get a great deal of attention.
In the industrial sector, companies such as Google, Microsoft, and Cisco are aiming to
relocate their server farms to the banks of rivers where hydroelectric power is readily
available, to Iceland for renewable geothermal energy, and to the Netherlands for renewable
wind power. These strategies not only help the companies build an image as environmentally-
friendly companies, but should also help them reduce their energy costs, and in particular,
reduce their Carbon footprints.
In the banking industry, a large Canadian financial services institution (FSI) already monitors
its energy usage from its commercial operations and is in the midst of implementing
strategies for energy conservation where feasible. However, this FSI would like to go beyond
its own effort by helping its customers implement energy-conservation techniques. This need
motivated this research. The goal of this research project was to develop and implement a
solution, in the form of a software algorithm, that would offer a residential energy
conservation tool for the FSI and its customers' use.
This project developed the algorithm of a web-application that would help the FSI’s customers
make financially-sound and environmentally beneficial decisions regarding energy-
conservation investments in their dwellings. The value of this project to the three primary
stakeholders (the FSI’s customers, the FSI, and the author) is manyfold. The FSI’s customers
who are looking to renovate their dwellings could obtain an estimate of the energy savings
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per dollar invested. The FSI itself will show that it is a good corporate citizen by showing the
community that the FSI cares for the environment in a meaningful way as a part of the way it
does its banking business. The FSI will also gain a vehicle to educate its staff (who will in turn
be better prepared to educate customers) about energy-conservation options. For the author,
this project provided an opportunity to apply the knowledge of chemical engineering and
engineering economics to the solution of a very practical and contemporary problem.
1.2 Problem Definition To achieve the goal of designing a meaningful calculator for the FSI, numerous discussions
were carried out with the FSI to elicit information that would determine their expectations.
Management’s intention was that the calculator would be used as an educational tool as well
as a planning tool for homeowners contemplating energy-related renovations. To meet these
dual goals it was decided that the calculator would aim to provide the following outputs:
• Financial impacts of various upgrades
• Impact on CO2 emission of various upgrades
• Impact of changes in future energy prices
• Impact of changes in carbon emission legislation
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Chapter 2 Background
2.1 Review of Academic Literature
A review of the academic literature was conducted to gauge the level of activity and interest
in the development of an energy savings calculator within the academic community. A
considerable amount of interest was found in tools intended for non-homeowner users (such
as equipment manufacturers, building energy auditors, policymakers, and architects), but
relatively little interest in calculators aimed at the homeowner. This section summarizes some
of the academic articles found in the review process.
Tools for Non-Homeowner Users
In 2006, Darius Sabaliunas et al. investigated the energy and CO2 savings achievable through
reducing operational water temperature for laundry in the United States and Canada
[SABA06]. They developed a model to quantify energy savings and consequently cost and
emissions savings for switching from hot/warm water usage to cold water in laundry
machines. They used publicly available average data for clothes washer annual water usage,
annual energy usage, energy costs, CO2 emissions, and demographic data for the US and
Canada to calculate a matrix of energy savings per load of laundry for numerous temperature
change scenarios, water heater fuel scenarios (gas or electric), and washer orientation
scenarios (front or top loading). The calculated household energy savings varied from 560 to
814 kWh per year, total household savings varied from $11.19 to $72.77 per year, and
annual CO2 emission reductions varied from 247 to 1259 lbs CO2 per year. Considering such
large variances in results it can be seen that a calculator that allows users to specify their own
particular inputs can deliver much more value than just an average savings amount calculated
using average input data. The article claims that a user friendly online calculator tool was
developed but it was not found at the mentioned website.
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In 2005, Harry D. Saunders published an article [SAUN05] on the design of a user-friendly
tool that allows policy makers to analyse the energy and cost effects of new energy efficient
technology. The article gives an overview of the calculation methods used in the tool, an
example of how to use the tool, and details on certain specifications used in the tool.
Interestingly, the tool does not use first-principle models to calculate energy savings and the
subsequent fuel cost savings. Instead, it utilizes correlations such as the ‘propensity’ of an
industrial sector to exhibit changes in response to a technology. It views the problem of
analysing the effects of energy efficient technology from an economist’s point of view rather
than an engineer’s. It was interesting to see the problem being addressed from a different
viewpoint.
Guler et al analysed the impact of energy efficient upgrades on the energy consumption of
houses in the Canadian housing stock [GULE01]. Guler et al utilized the Canadian Residential
Energy End-use Model (CREEM) to perform their analysis. They calculated the base energy
consumption of houses in CREEM by using the energy simulation program HOT2000 and then
calculated the energy savings of various upgrades by calculating the energy consumption of
the houses after applying the upgrades, running a new simulation on HOT2000, and
calculating the difference in energy consumption. The upgrades considered included better
building envelope insulation, heating systems, thermostats, lighting, showerheads, etc. They
concluded that the energy savings of all the upgrades were only 0 – 8% of the total energy
consumption of the Canadian housing stock. The payback periods for most upgrades were too
long with the exception of upgrades such as additional basement insulation at 7 years,
replacement of incandescent light bulbs (ILB) with compact fluorescent light bulbs (CFLB) at 2
years, replacement of standard showerheads with low-flow ones at 0.4 years, and
replacement of standard thermostats with programmable ones at 6 years. These are
interesting results because they give us a general understanding that most upgrade projects
may not be worthwhile from a financial point of view. However, these results are highly
dependent on the numbers used for the price of energy, cost of upgrades, the amount of
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energy used by the household and it would be interesting to see a sensitivity analysis of the
energy savings and payback period calculation to all these factors, which was not provided in
the paper. Furthermore, calculations of the environmental impact of the upgrades in terms of
CO2 emission reductions were not performed by the authors. Finally, the type of analysis
presented may be of value on a community level where public policy with regards to
residential energy consumption is set, however, it is of little use to a specific homeowner who
would like to know the impact of specific upgrades to his/her own house.
In 1999, Teresa Forowicz of the Lawrence Berkley National Laboratory published an article
[FORO99] on a algorithm for modeling building energy demand using an HTML interface. The
article explains how results from over 10,000 energy simulation performed using a software
called DOE-2.1 are used to estimate energy usage in different houses. The article, however,
does not give any sample calculation or worked examples so it is difficult ascertain the true
value from the implementation of such a scheme. It is envisioned that such a tool would be
used by building energy auditors as it enables them to compare the building being audited to
others present in the database. The tool would be of little use to homeowners since it does
not have specific means of calculating the energy and cost savings of installing specific
upgrades.
In 2002, Elisabeth Gratia et al. of the Université Catholique de Louvain, Belgium published an
article [GRAT02] describing the development of a tool aimed at helping architects see the
impact of their design choices on the energy consumption of the house. The software tool was
designed with elements of user-friendliness, speed, and minimum user input in mind. The
article describes in detail a number of problems that were encountered and how they were
solved. For example, it claims that building energy simulations typically take a long time to
perform and require an overwhelming amount of input data. To overcome these problems,
many simulations were performed for different house shapes beforehand and the results were
stored in databases. Then, only a few parameters were used to interpolate the results from
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the database to generate results for a particular house design during runtime. This made the
software very fast. The article describes that the tool is able to provide users the effect of
factors such as window area, window type, orientation, insulation level, shading, etc. on the
energy consumption of the house. It can be seen that such a tool would be quite useful for
architects but a similar tool that could show homeowners the effects of elements such as
various window types and insulation levels would be quite beneficial to the homeowner.
Unfortunately, no tool of this sort, aimed at the homeowner, was found within the academic
literature.
Energy Savings Calculators for the Homeowner
In 2004, Evan Mills form the Lawrence Berkley National Laboratory (LBNL) published a
thorough article [MILL04] comparing various energy analysis tools available that are aimed at
the homeowner. Mills evaluated numerous web-based (operated through an internet browser)
and disk-based (operated though the operating system without a browser) tools available at
the time. Interestingly, Mills’ was the only academic article found that discussed calculators
aimed directly at the homeowner.
Mills published some valuable observations and findings that resulted from his study. He
noted that there is an overwhelming number of choices of calculators available to the
homeowner and they often produce conflicting results. He wrote that the sources of observed
differences in results are difficult to pinpoint and for tools that predicted the gross household
energy usage the results varied by nearly a factor of three. Mills claims that surprisingly many
calculators provide only energy consumption predictions but provide no estimated potential
energy savings, and even fewer provide cost-effectiveness or CO2 emissions analysis. This
trend was also observed in our own review of other existing calculators described in section
2.3. Mills also recommends that particular attention be given to the intended use and the
target audience (such as delivering decision supporting information to the homeowner as
opposed to conventional engineering outputs).
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2.2 Energy Saving Technologies
As a result of pressure from federal regulators, the need and/or want to uphold corporate
social responsibility, and due to market forces, manufacturers of home appliances and HVAC
(heating, ventilation, and air-conditioning) equipment have continuously improved the design
of their products to help homeowners save energy. In most cases manufacturers attempt to
make their devices more energy efficient, i.e. the device achieves the same output using less
energy by reducing its wastage of energy, such as in a high-efficiency furnace, but in other
cases they invent new products that can help conserve energy when installed in conjunction
with existing devices in the house, such as a programmable thermostat.
In this section, 7 potential energy conserving technologies are discussed. Each discussion
follows the same general format of describing the technology, how it saves energy, how
easy/difficult the upgrade is to perform, how energy-related information about the technology
is communicated by the manufacturer, and a survey of prices of typical products available on
the market.
It can be seen that the cost of most products varies as a function of manufacturer, brand,
beneficial features, over and above just the efficiency, and size of the product and thus there
is no clear way to predict the price of any products from a few user-answered questions. It is
thus best to ask the users to enter the actual cost themselves. Furthermore, users are
routinely able to obtain discounts from their contractors for certain product models, they may
be able to find discounted items on auction websites such as ebay.ca, and they may also be
eligible for municipal and provincial grants from their local governments. This makes the cost
of the product to the homeowner even more unpredictable and unique. Thus, it is necessary
that the users be allowed to enter their own cost that is unique to their situation.
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Higher Efficiency Furnace
In a furnace, fuel such as oil or natural gas is combusted in a controlled manner and this
exothermic reaction produces heat that is used to warm homes in cold climates to maintain
comfortable temperatures indoors. The amount of heat released per unit of fuel burned, or
the specific enthalpy of combustion, is a natural constant of 35.5 kBTU/m3 for natural gas and
is the maximum that can be possibly generated in the furnace. However, it is the amount of
heat recovered per unit fuel burned that changes from furnace to furnace. High-efficiency
furnaces are able to recover a very large percentage of the heat of combustion, letting only
very little heat go to waste. They are able to achieve this by reducing the temperature of all
the waste products of combustion before venting them (thus recovering heat from them) and
using this heat to preheat the air going into the furnace. In fact, in a condensing furnace,
water vapour (one of the main products of combustion) is cooled so much that it condenses to
liquid water which is then disposed through a drain. Older, lower efficiency furnaces normally
vent water as a vapour out the top of houses and it is the condensing of the water vapour as
it mixes with the frigid air outside that creates the white smoke clouds that are traditionally
visible from the tops of old houses. With the high-efficiency furnace the only significant waste
product that gets vented as a gas through the top of the house is CO2, but only after it has
been cooled to recover all of the recoverable heat from it. In fact, the vented CO2 is cool
enough that it can be vented through a plastic pipe eliminating the need for a metal pipe that
would otherwise be required to vent the hot gases from a low-efficiency furnace.
Figure 2-1 A typical natural gas fired furnace
Source: http://www.alpinehomeair.com/viewcategory.cfm?categoryID=216
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Upgrading to a high-efficiency furnace from a lower efficiency one should not be a difficult
task. Setup costs for such an upgrade should be quite low since all of the distribution network
that takes heated air from the furnace (which is usually located in the basement) to the rest
of the house, the pipe network that delivers natural gas to the furnace from the main utility
line located outside the house, and the stack that vents the waste gases out of the house are
already in place for the older low-efficiency furnace. The upgrade only requires the
replacement of the old furnace unit with the new one and the adjusting of the various
connections into the existing infrastructure.
In the process of quantifying the energy and cost savings achievable from the upgrade it will
become important to be familiar with the terminology used to pragmatically convey the
theoretical energy-related information about the manufacturer’s product and their meaning. It
is also important to know how readily accessible this information is to a purchaser of the
product such as the homeowner. The most important data for the case of the furnace is the
annual fuel utilization efficiency (AFUE). The AFUE gives a measure of the efficiency of the
furnace determined by running a standardized test simulating the furnace’s operation over a
year.
It was found that prices for high-efficiency furnaces can vary from $649.99 to $1,242.99 for a
typical house. Table 2-1 shows a sample of the data that was collected.
Table 2-1 Furnace prices
Manufacturer Model# Capacity (BTU/hr) AFUE Price
Goodman GDH80453AX 45,000 80% $647.99 Goodman GMH950453BX 46,000 95% $850.99 Goodman GDH81155CX 115,000 80% $873.99 Goodman GCH90453BX 46,000 93% $938.99 Goodman GMH950905DX 92,000 95% $1,058.99 Goodman GMH951155DX 115,000 95% $1,121.99 Goodman GCH91155DX 115,000 93% $1,242.99
Source: http://www.alpinehomeair.com/
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Heat Pump
A heat pump is a device that uses the heat pump cycle [HPNRC] to move heat from one
position to another against the heat gradient. As opposed to a furnace that heats a dwelling
by utilizing the heat energy released from the combustion of fuel, the heat pump simply
‘pumps’ the heat energy available in a large heat reservoir into the dwelling. This large heat
reservoir could be the earth underground, as for a ground source heat pump (GSHP), or the
outdoor air, as for an air source heat pump (ASHP). To give a familiar example, the air
conditioner used to cool a dwelling is actually a heat pump that moves heat from the inside to
the outside in the hotter months. The heat pump just operates in reverse to heat the dwelling
in the cooler months. Figure 2-2 shows a typical heat pump commercially available.
The efficiency of a heat pump is measured by its heating coefficient of performance (HCOP).
The HCOP measures how much heat energy is provided by the heat pump per unit of
electricity consumed. For example a HCOP of 2.0 means that 2.0 kWh of heat is provided for
every kWh of electricity consumed. However, the efficiency may also be expressed by the
heating seasonal performance factor (HSPF) where the efficiency is expressed as a ratio of
heat provided in kBTU to electricity consumed in kWh. Therefore, a HSPF of 6.8 kBTU/kWh is
equivalent to a HCOP of 2.0 since 3.4 kBTU is equal to 1 kWh.
Figure 2-2 A typical heat pump available on the market
Source: http://www.alpinehomeair.com/viewcategory.cfm?categoryID=136
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Table 2-2 Heat pump prices
Manufacturer Model# Capacity (BTU/hr)
HSPF (kBTU/kWh) Price
Goodman GSH130181 16,800 8.0 $1,175.99 Goodman GSH140181 18,000 8.3 $1,369.99 Goodman SSZ140241 24,000 8.5 $1,469.99 Goodman SSZ160241 24,000 9.5 $1,949.99 Goodman DSZ160241 24,000 9.5 $2,099.99 Goodman GSZ130601 58,000 8.6 $2,110.99 Goodman GSH140601 55,000 9.0 $2,362.99 Goodman SSZ140601 58,000 9.0 $2,486.99 Goodman SSZ160601 60,000 9.75 $3,228.99 Goodman DSZ160601 60,000 9.75 $3,370.99
Source: http://www.alpinehomeair.com/
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Programmable Thermostat
A thermostat is a controller device that autonomously adjusts the operation of a heating
system (such as a gas furnace) to maintain a certain temperature range. When temperature
readings received by the thermostat from temperature sensors show that the temperature
has fallen below a certain threshold level, set by the house occupants, the thermostat sends a
signal to switch the heating system on. The heating of the house raises its temperature and
the heating system is kept on until the thermostat senses that the temperature has gone
above another preset threshold level. The thermostat then sends a signal to switch the
heating off and the house temperature gradually starts to decline as heat is lost through the
building envelope. The thermostat continues switching the heating on or off as house
temperatures fall below or above preset levels, in effect, maintaining the temperature at the
desired levels.
However, traditional thermostats maintain the houses temperature around one set level. If
set at say 23°C they will only maintain the house temperature at around 23°C (i.e. within a
narrowly defined range above and below the set temperature where the range is usually pre-
programmed by the manufacturer) whether that temperature may or may not be required.
For instance, in a house with only working or school-going occupants, the house is empty
during the working hours on a weekday and does not need to be maintain a comfortable
temperature of 23°C. Furthermore, at night when occupants are sleeping and have insulating
comforters over them it is actually more comfortable for the room temperature to be slightly
lower. Reducing the temperature set at the thermostat reduces the amount energy the
heating system has to provide and thus saves energy, but continually having to change the
set temperature when leaving for work or going to sleep can get cumbersome and is likely to
be forgotten. A programmable thermostat solves this problem by allowing the user to store in
the device’s memory what temperatures are desired at what times. After this one time entry,
the programmable thermostat automatically sets the thermostat to the varying temperature
requirements of the day.
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Figure 2-3 shows what a programmable thermostat looks like compared to a non-
programmable thermostat. As an added bonus, the LCD panel of the programmable one has
an appealing modern appearance giving it the edge of being more aesthetically pleasing over
the non-programmable one.
Figure 2-3 Image of a programmable thermostat (left) and a non-programmable one (right)
Upgrading from a traditional thermostat to a programmable one is so simple that it can even
be performed by the homeowner him/herself. The old thermostat already has attached to it
all the wires required to control the operation of the heating system so all that has to be done
is that these wires, which are colour or letter coded, have to be taken off the old thermostat
and attached to the new programmable thermostat ensuring that the colour codes match up.
Figure 2-4 from the installation manual of a Honeywell programmable thermostat shows how
the new back plate of the thermostat is mounted on the wall in the same place as the old
thermostat, the wires are connected, and then the front face of the thermostat is snapped
into place [HONE05].
Source: http://www.homedepot.ca/webapp/wcs/stores/servlet/CatalogSearchResultView?D=977129&Ntt=977129&catalogId=10051&langId=-15&storeId=10051&Dx=mode+matchallpartial&Ntx=mode+matcha
Source: http://homerepair.about.com/od/heatingcoolingrepair/ss/thermostat.htm
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Figure 2-4 Installing a new programmable thermostat The energy that programmable thermostats save is quite independent of the characteristics of
the thermostat itself since the energy saving is only determined by the pattern of
temperature variations that the user programs. As such there is no specific energy-related
information or terminology for the programmable thermostat that has to be learned about or
that the online calculator will ask the user.
Programmable thermostats are relatively inexpensive. From the survey conducted, they cost
on average about $90 and within the surveyed data the range of prices is from $34.00 to
$189.00. This survey data is presented in table 2-3 and it can be seen the price varies by
manufacturer, the thermostat type, and the source of the product information. The
programmable thermostats tend to come in three types: 7 day, 5-2 day, and 5-1-1 day. This
type refers to amount of variability in daily temperature patterns during a week that the
thermostat can store. A 7 day type can only store one temperature pattern that it repeats
daily for 7 days of the week. A 5-2 day type can store two different temperature patterns, one
for the 5 weekdays and one for the 2 days of the weekend, and the 5-1-1 day type stores
three different patters and it therefore allows a different pattern for Saturday, Sunday, and
the rest of the weekdays.
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Table 2-3 Price survey of commercially available programmable thermostats
Manufacturer Model# Type Price Source Honeywell YRLV4300A1006 5-2 day $34.00 Home Depot
UPM THM501 7 day $38.67 Ebay.ca Honeywell YRLV4300A1014 5-2 day $39.99 Home Depot Honeywell RTH2310B1010 5-2 day $49.00 Home Depot
Aube TH106 7 day $49.99 Home Depot Honeywell RTH4300B1026 5-2 day $59.99 Home Depot
Carrier TS32HFD N/A* $65.18 Ebay.ca Aube TH141HC-28 7 day $65.73 Ebay.ca
Honeywell RTH6400D1018 5-1-1 day $79.99 Home Depot Honeywell YRTH7500D1058 7 day $119.00 Home Depot Honeywell RTH7600D1014 7 day $119.00 Home Depot SunTouch 81010169 N/A* $119.98 Home Depot Honeywell YRTH8500D1040 7 day $139.00 Home Depot
True Comfort PS120/240TP N/A* $179.99 Home Depot Honeywell HW240B N/A* $189.00 Home Depot
*N/A = Information not available Home Depot = http://www.homedepot.ca/ Ebay.ca = http://www.ebay.ca/
16
Better Insulation
Insulation is installed in all elements of a building’s envelope (walls, roofs, floors, etc.) in cold
climates. It is made of materials that are good at reducing the flow of heat and they help
reduce the loss of heat energy from the heated interior of the dwelling to the colder outdoors.
Energy can be saved by upgrading insulation by increasing the thickness of insulation or by
using a material that is better at reducing the flow of heat through the building envelope.
Figure 2-5 shows where insulation is placed in the wall of buildings and in the attic. It can be
seen that since the insulation is actually encased inside the wall it can be quite difficult to
upgrade the insulation in walls. However, insulation that is placed in the roof of houses, just
on the floor of the attic, can be particularly easily upgraded.
Figure 2-5 Position of wall insulation and attic insulation
The energy related information for insulation is communicated through the R-value. The R-
value is a measure of the thermal resistance of the insulation and has the SI units of K.m2/W.
When the R-value is expressed in SI units it is actually known as the RSI value to differentiate
Source: http://c.managemyhome.com/Images/Insulation_and_ventilation/Ventilation/1382_R.gif
Source: http://content.managemyhome.com/Images/Insulation_and_ventilation/Ventilation/1345_R.gif
17
it from the R value which is expressed in ft²·F°·h/Btu units. Table 2-4 shows a survey of
prices of some insulation.
An important concept that is used in the calculation of heat loss through building envelope
insulation is the heating degree days (HDD). HDD is defined as the sum over the period of a
year of the difference between the daily average outdoor temperature and a base
temperature (typically 18°C) for days when the average temperature is below the base
temperature. The daily average outdoor temperature is calculated by taking the average of
the day’s high and low temperatures. The HDD then provides an indication of how much
heating is required to maintain a comfortable indoor temperature of about 18°C. In section
3.4 it is shown how the HDD is actually used for calculation purposes.
Table 2-4 Price survey of building envelope insulation
Type Material RSI (m2.K/W)
Thickness (cm)
Price ($/m2)
Blown Cellulose 2.3 8.9 5.46 Blown Fibreglass 1.9 12.5 6.41 Blown Mineral Wool 2.1 10 6.96
Blanket Mineral fibre 2.1 8.8 7.59 Blanket Fibre glass 1.9 8.8 8.68 Blanket Mineral fibre 3.4 15 8.97
Loose-Fill Mineral wool 2.0 10 9.60 Blanket Fibre glass 3.3 15 9.97
Loose-Fill Fibreglass wool 2.8 10 10.04 Loose-Fill Cellulose fibre 2.8 10 10.55 Loose-Fill Wood fibre 2.8 10 10.80 Blanket Mineral fibre 5.3 25 12.36
Loose-Fill Ceramic 2.4 10 14.70 Blanket Fibre glass 6.7 30 15.57
Loose-Fill Polystyrene 2.8 10 20.00 Sprayed Foam 2.8 10 93.32
Source: http://rsmeans.reedconstructiondata.com/
18
Higher Efficiency Window
Windows, being part of a building envelope, have to serve the function of preventing heat
transfer. In the window, heat transfer is slowed down by using double or even triple glazing.
A double glazed window is one in which there are two separate panes of glass separated by a
layer of gas. As this gas has a much lower coefficient of heat transfer than glass, it gives the
whole window a coefficient of heat transfer much lower than that of glass itself. This overall
coefficient of heat transfer is represented and communicated by window manufacturers by U.
The lower the U of a window, the better are its insulating properties and thus the more it can
help conserve energy. Figure 2-6 shows a typical single, double, triple glazed window.
However, windows being transparent also allow the sun’s radiant energy to enter into a
dwelling. This energy is welcome in the winter months when it helps heat the dwelling’s air
reducing the demand on space heating equipment. A window’s ability to let sunlight through
is known as its solar heat gain coefficient (SHGC). For the cold climate of Canada, the higher
the SHGC of the windows, the better they are at enabling space heating energy conservation.
A window is considered more efficient if it has a lower U and a higher SHGC.
Figure 2-6 Picture of single (left), double (middle), and triple (right) glazed windows
Table 2-5 Price survey of windows (including installation cost)
Source: http://media.rd.com/dynamic/64/35/39/200701_TripleGlaze_001.jpg Source:
http://www.progressivewindowsinc.com/progressive/inter.php?page=wic&sub=glass
19
Type Frame Material Size Glazing Total Installed
Cost ($) Awning Wood 6’ x 5’ Single 533.50
Casement Wood 4’ x 6’ Single 898.00 Casement Wood 8’ x 5’ Double 1854.00
Bow Wood 8’ x 6’ -- 2099.00 Single Hung Aluminum 3’-4”x5’ Standard 382.00
Sliding Aluminum 8’ x 4’ Standard 479.00 Sliding Aluminum 9’ x 5’ Insulating 1031.00
Source: RSMeans - http://www.meanscostworks.com/
20
Higher Efficiency Lighting
The purpose of lighting is to convert electrical energy to light, however the technology used
by light bulbs to achieve this purpose is quite varied and thus the efficiency of the process is
quite varied as well. The more recent compact fluorescent light bulb (CFLB) produces light
with much higher efficiency than the traditional incandescent light bulb (ILB).
To understand how the CFLB is more efficient than the ILB it is helpful to know how these two
bulbs actually convert electricity to light energy. The ILB channels electric current through a
thin metal wire (typically tungsten) of suitable characteristics (such as resistivity) in order
that the resistance experienced by the current heats up the metal wire to such a high
temperature that it glows releasing light. However, along with the production of light the
majority of the electricity is converted into heat energy that is not perceived by the human
eye. It is this loss of electricity to heat that gives rise to the inefficiency of the ILB. In the
CFLB, electric current is used to ionize some atoms of gas (typically mercury vapour) residing
in the CFLB. The ionized atoms then transfer their charge to other non-ionized atoms,
returning to their ground state electronic configuration and producing photons of light in the
process. It is these photons that are perceived as light from the CFLB. Since this process does
not require the significant heating up of any component it is much more efficient at converting
electricity to light energy.
Figure 2-7 shows an image of a typical ILB and a typical CFLB. The installation process
required to upgrade an ILB to a CFLB is extremely simple. The ILB is unscrewed from its light
fixture and a CFLB is screwed into its place. Thus there is really no installation cost that the
homeowner needs to consider.
21
Figure 2-7 Image on a typical ILB (left) and CFLB (right)
The only energy related information that is required to be known for this upgrade is the power
consumption of the bulbs. All bulbs come with their power consumption rate printed on them
and this information relays how much electricity the bulb consumes every second. For
example, a 10 watt (W) bulb consumes 10 joules of energy every second. To calculate the
energy saved by upgrading an ILB to a CFLB the difference in power consumption between
the two bulbs is determined and is then multiplied by the time the bulb is used per annum.
Table 2-5 shows some of the prices observed upon survey. The rows are sorted by the CFLB
power consumption rate. It can be seen that there is no clear trend in pricing as a function of
power or even brand. Thus the price of the CFLB cannot be automatically determined for the
user’s convenience but has to be left for the user to enter. Within the prices surveyed the
minimum was $2.16 and the maximum was $17.98 showing a large variance in price but
nevertheless all these prices show that upgrading a bulb requires a relatively small capital
investment.
Source: http://dvice.com/pics/bulb_old_new.jpg
22
Table 2-6 Price survey of commercially available CFLBs
Company Brand Model# Price ($)
CFLB Power (W)
ILB Equivalent
(W)
Light Output
(Lumens) Life (hr) Source
Philips Mini Twister 210906 3.99 9 40 550 10,000 Home Depot
Philips Daylight 210591 2.16 13 60 900 10,000 Home Depot
Philips Mini Twister 210914 3.99 13 60 900 10,000 Home Depot
Philips Marathon 137075 14.98 16 65 630 8,000 Home Depot Philips Marathon 146449 17.98 20 75 850 8,000 Home Depot Philips Marathon 210955 4.99 23 100 1,600 10,000 Home Depot Philips Marathon 157024 14.98 23 85 1,250 8,000 Home Depot Philips Marathon 139774 12.98 42 150 2,800 12,000 Home Depot
Home Depot: http://www.homedepot.ca/
23
Higher Efficiency Refrigerators
Refrigerators are used to keep food and drinks cold by continuously removing the heat from
inside an insulated box. A refrigeration cycle is similar to the one used for a heat pump and is
used to ‘pump’ the heat out of the cold box into the warmer room where the refrigerator is
placed essentially against the direction which heat will spontaneously move, i.e. against the
temperature gradient. This transfer for heat energy is achieved by using electricity to power
the compressors.
There are a lot of complex systems that are amenable to being designed, manufactured, or
operated in an inefficient manner that leads to energy wastage. Energy Star claims that
refrigerators currently qualified under their program require about half as much energy as
models manufactured before 1993 [ESRE]. Efficiency is improved by using high efficiency
compressors, and better insulation amongst other technical approaches. Furthermore, some
design schemes also help improve efficiency such as designing the freezer to be at the bottom
of the unit rather than at the top. Cold air being denser than warm air it tends to “fall” out of
a top-mounted freezer when it is opened warming up the freezer and wasting energy. Putting
the freezer at the bottom and making it open like a drawer rather than a door reduces this
energy loss. Upgrading a refrigerator only requires that the current refrigerator be unplugged
from the electric power socket and the new one be plugged in, and so it is not a very involved
procedure.
Energy related information for refrigerators is communicated in a very convenient manner. All
new refrigerators come with an EnerGuide label that clearly displays the refrigerators annual
electrical energy consumption. Figure 2-8 shows an example of such an EnerGuide label.
However, there are some other methods of determining a refrigerator’s annual energy
consumption in case the EnerGuide label is not available. These methods are discussed in
chapter 3 under the section dealing with refrigerator upgrade.
24
Figure 2-8 Sample EnerGuide label for a refrigerator
Table 2-6 shows a survey of prices for new refrigerators. The rows are arranged by ascending
refrigerator price which ranges from $429.00 to $4,669.00. It can be seen that the price
shows no good functional relationship to characteristics such as the total capacity or the
annual energy consumption. Thus, yet again, it is best if the cost field is left for the user to fill
in.
Source: http://oee.nrcan.gc.ca/residential/business/energystar/most-energy-efficient.cfm?attr=4
25
Table 2-7 Price survey of new refrigerators
Brand Model# Refr. Vol
Freezer Vol
Total Capacity (cu. ft.)
Freezer Location
Defrost Mechanism Ice
Energy Star
Qualified
AEC (kWh) Price Price
Source
Danby DFF8803W N/A N/A 8.8 Top Auto No No 373 $429.00 AjMadison Danby DAR1102WE 11.0 0.00 11.0 None Auto No Yes 306 $499.00 AjMadison Danby DFF9102W 6.86 2.26 9.1 Top Auto No No 376 $519.00 Home Depot
GE GTS18GBSWW 13.89 4.27 18.2 Top Auto No No 480 $599.00 Home Depot Frigidaire GLHT184TJ 14.27 4.07 18.3 Top Auto No Yes 383 $599.00 AjMadison
GE GTK18ICXBS 12.93 5.09 18.0 Top Auto No Yes 387 $939.00 AjMadison LG LTN19315SB 13.7 5.3 19.0 Top Auto No No 485 $949.00 Home Depot
Amana ABB2221FEB 15.6 6.3 21.9 Bottom Auto No No 488 $1,009.00 AjMadison Amana ASD2522WRD 15.2 9.9 25.1 Side Auto Yes Yes 577 $1,019.00 AjMadison Amana ABB1922FEQ 12.9 5.6 18.2 Bottom Auto No Yes 448 $1,059.00 AjMadison U Line 2115R 3.3 0 3.3 None Auto No Yes N/A $1,159.00 AjMadison
LG LDN20718ST 13.4 6.3 19.7 Bottom N/A No Yes 454 $1,649.00 Home Depot Heartland 3165 14.6 5.6 20.2 Bottom Auto No Yes 481 $4,179.00 AjMadison
GE PSB42YGXSV 15.6 9.6 25.2 Side Auto Yes No 606 $4,669.00 AjMadison AEC = Annual Energy Consumption AjMadison: http://www.ajmadison.com/ Home Depot: http://www.homedepot.ca
26
2.3 Other Existing Calculators
There are many residential energy-related calculators available on the internet. They range
from the very basic ones that do not appear to fulfill a useful need to the much more complex
and more useful ones. Table 2-7 lists some of the most popular calculators discovered and
their website addresses.
Table 2-8 List of Other Existing Calculators
1 Home Energy Saver - Lawrence Berkeley National Laboratory http://hes.lbl.gov/
2 Energy Star – Canada http://oee.nrcan.gc.ca/residential/business/energystar/procurement/calculator.cfm?attr=4
3 Energy Star – US http://www.energystar.gov/
4 Home Energy Calculator - Manitoba Hydro http://www.hydro.mb.ca/energy_calculator/index.html
5 powerWISE Calculator - powerWISE http://powerwise.ca/resources/powerwise-calculator/
6 Energy Calculator - Nova Scotia Power http://www.nspower.ca/en/home/energyefficiency/Energy_Calculator.aspx
7 Energy Efficient Rehab Advisor - U.S. Dept. of Housing and Urban Development http://www.rehabadvisor.pathnet.org/index.asp
8 ZIP-Code Insulation Program – Oak Ridge National Laboratory http://www.ornl.gov/~roofs/Zip/ZipHome.html
9 Energy Cost Calculator - US Department of Energy http://www1.eere.energy.gov/femp/procurement/eep_eccalculators.html
10 Heating Cost Calculator – The Weather Network http://www.theweathernetwork.com/index.php?product=wxhome&placecode=caon0696&pagecontent=heating_cost
11 RETScreen – Natural Resources Canada http://www.retscreen.net/ang/home.php
12 Conservation Calculators – Ontario Ministry of Energy and Infrastructure http://www.mei.gov.on.ca/english/energy/conservation/?page=calculators
13 Energy Cost Calculator – Take Charge http://takechargenl.ca/WaysToTakeCharge/EnergyCostCalculator.aspx
14 Home Heating System Cost Calculator – Natural Resources Canada http://oee.nrcan.gc.ca/residential/personal/tools/calculators/heatingcalc/index.cfm
15 Replacing Your Furnace – Canada Mortgage and Housing Corporation http://www.cmhc-schl.gc.ca/en/co/renoho/refash/refash_018.cfm
16 Energy Cost Calculator for New Appliances - Natural Resources Canada http://oee.nrcan.gc.ca/residential/personal/appliances/energy-cost-calculator.cfm?attr=4
17 An Inconvenient Truth CO2 Calculator http://www.climatecrisis.net/takeaction/carboncalculator/
18 HOT2000 – Natural Resources Canada http://canmetenergy-canmetenergie.nrcan-rncan.gc.ca/eng/software_tools/hot2000.html
19 Hot2XP – Natural Resources Canada http://canmetenergy-canmetenergie.nrcan-rncan.gc.ca/eng/software_tools/hot2xp.html
20 Home Energy Suite – WPPI Energy http://wppi.apogee.net/homesuite/calcs/rescalc/default_supp.aspx
27
The calculators in table 2-7 were investigated to determine what purpose they serve, what
type of user input they require, and what their strengths and shortcomings are. It was
observed that it is not easy to generalize the result of that investigation since the calculators
serve quite diverse purposes, ask for quite different types of user inputs, and their
strengths/shortcomings are varied as well. Hence, in order to judge the value that they
deliver against a common measure, it was thought useful to see if they fulfil any of the 4
goals laid out in the problem definition in Chapter 1. Table 2-8 present the results of that
investigation and the 4 goals are reproduced under the table. A fifth criterion was added to
check if the calculator’s target user is the homeowner. A tick shows that the calculator meets
that criteria in some manner, and a “No” shows that it does not.
Reviewing table 2-8 it can be seen that many of the calculators do not meet the goals set out
for the research project. This means that we may have found needs that are not being met
adequately. It can be seen that none of the calculators allow the user to see the impact of
changes in carbon emission legislation, i.e. the effect of a carbon tax. Interestingly, the two
calculators that meet the most number of the 4 goals (calculators 18 and 19) are not
designed for the homeowner.
To give a better visualization of some of these calculators two of them are showcased in this
section. Out of the two, one was picked because it does not meet any of the goals (#4), and
the other was picked because it meets most of the goals and is designed to be used by the
homeowner (#1). For ready reference these calculators are:
#4: Home Energy Calculator - Manitoba Hydro
#1: Home Energy Saver - Lawrence Berkeley National Laboratory
28
Table 2-9 Value delivered by calculators judged against the criteria listed below
Criteria:
1. Financial impacts of various upgrades
2. Impact on CO2 emission of various upgrades
3. Impact of changes in future energy prices
4. Impact of changes in carbon emission legislation
5. Calculator designed for the homeowner
Criteria Calculator
1 2 3 4 5
1 No No
2 No No
3 No No
4 No No No No
5 No No No No
6 No No No No
7 No No No
8 No No No No
9 No No No
10 No No No No
11 No No
12 No No No
13 No No No No
14 No No No
15 No No No No
16 No No No No
17 No No No No
18 No No
19 No No
20 No No
29
Home Energy Calculator - Manitoba Hydro
Manitoba Hydro’s Home Energy Calculator is one that is quite basic. As shown in figure 2-9 it
starts by prompting the user for inputs such as the type of dwelling, area in square feet,
geographical location, space heater type, insulation quality, water heater type, and the
number of occupants.
Figure 2-9 First Set of Inputs for Manitoba Hydro’s Calculator
Next the calculator takes the user to a series of pages like the one shown in figure 2-10
where information about appliances and other energy users can be entered. It can be
deduced that one good feature of this page is that it shows the user what the average rate of
energy consumption the calculator assumes for each device added and its average monthly
hours of usage. It also allows the user to edit both these values giving the user control over
the default values. This is good because it lays down the assumptions that the program uses
Source: http://www.hydro.mb.ca/energy_calculator/index.html
30
giving by a knowledgeable user more confidence over the workings of the calculator, and, of
course, the ability to change it to suit his/her requirements. However this feature is limited in
its usefulness for a less knowledgeable user as can be illustrated for the particular example
shown in figure 2-10 regarding the energy consumption of a refrigerator. The tool does not
give the user any information about the dependence of the refrigerator’s average power
usage on its size and so a user with an appliance smaller or larger than the average size could
receive quite an inaccurate result.
Figure 2-10 Detailed Input for Manitoba Hydro’s Calculator
Source: http://www.hydro.mb.ca/energy_calculator/index.html
31
The result generated by inputting only the information from the above two figures is shown in
figure 2-11. The calculator outputs the dwelling’s monthly and yearly “predicted” space
heating costs, and the monthly and yearly cost of running the appliance whose data was
entered previously.
Upon a critical analysis of the accuracy and utility of this result a few noteworthy points arise:
1. The calculator does not display how it predicted the heating costs and what
assumptions it made towards this end, which brings the accuracy of the heating costs
into question.
2. Space heating cost can be determined by a user by simply looking at his/her heating
bill which raises questions about the utility of this result.
3. The calculator does not show the user what unit price of electricity or natural gas it
uses thus compromising the user’s confidence in the energy cost figures.
4. The results do not give any indication of the CO2 emitted by this energy usage.
5. The results regarding the refrigerator give no indication as to the energy-efficiency of
the device or what amount of energy could be saved by switching to a more efficient
device.
As such, it becomes quite clear that the utility of such a calculator is not very high.
32
Figure 2-11 Output Report from Manitoba Hydro’s Calculator
Source: http://www.hydro.mb.ca/energy_calculator/index.html
33
Home Energy Saver - Lawrence Berkeley National Laboratory (LBNL)
This is a calculator that meets many of the 4 goals and is well designed for the homeowner.
At the outset the calculator asks for the user’s zip code as shown in figure 2-12. It is clear,
right at the start, that this calculator is designed only for the US market because it is not
possible to move on in the program without an American zip code.
Figure 2-12 First screen of the Home Energy Saver - LBNL calculator
For the purpose of this investigative showcase of the Home Energy Saver an arbitrary Buffalo,
New York zip code (14209) was entered. The city of Buffalo was preferentially chosen as it is
close in proximity and climate to a Canadian city such as Toronto and so will lead to output
that would be of interest to the colder Canadian climate much more than the warmer climate
of say a Californian city. Entering the zip code leads the user to the screen shown in figure 2-
13. Here the annual energy cost of an average home and that of an energy efficient home in
the area near the zip code is displayed.
Source: http://hes.lbl.gov/
34
Figure 2-13 Second screen of the Home Energy Saver - LBNL calculator This screen proceeds to ask the user questions pertaining to their household such as the year
of construction of the house, the number of refrigerators, the number of stories, etc. as
shown in figure 2-13. The user may choose to answer the questions or leave the answers as a
default. Furthermore, the user can also answer more specific questions about energy
consumption systems in their home by clicking on the tabs at the top such as ‘Heating &
Source: http://hes.lbl.gov/
35
Cooling’, ‘Water Heating’, ‘Major Appliances’, etc. For example clicking on the ‘Water Heating’
tab takes the user to the screen shown in figure 2-14 where they can provide information
about the year of purchase, whether they pay for their water heater fuel, and so on as shown
in the figure.
Figure 2-14 Screen for detailed input for water heater
After having answered all the questions the user cares to answer, the user is taken to the
final upgrade recommendation screen like the one shown in figure 2-15. Here the user is
shown upgrade scenarios ordered by simple payback period. The user is shown the cost of
energy saved by the upgrades, the typical estimated cost of performing the upgrade, and
various financial measures relating to the upgrades.
Source: http://hes.lbl.gov/
36
Figure 2-15 Screen showing final upgrade recommendations Source: http://hes.lbl.gov/
37
This is what the Home Energy Saver (HES) has to offer in essence. At face value it appears to
deliver a strong value proposition to the homeowner. Documentation on the HES [HES07]
shows that the software was initially developed over a period of at least 2 years by a team of
at least 34 people in 1996 and its design has been under improvement ever since. The use of
such a sizeable pool of resources is evident from the vastness of the software. However, the
shortcomings of this impressive calculator become evident following a more detailed review.
From the user’s point of view, five important shortcomings of the HES come to light:
1. The calculator does not allow the user to specify the details of the base case or the
upgrade case thus foregoing a valuable comparison. For the case of upgrading the
water heater (figure 2-14), for example, the user cannot specify the efficiency of the
base case water heater (which would be available to the more savvy users) or the
technology-type (tankless or tank type) of the water heater. In fact, the user may
even want to make financial comparison between two new water heaters: one with a
tank and one without, however, this type of comparison is not facilitated by the HES.
2. The HES does not allow the user to change the CO2 emission amount per kWh of
electricity. This emission amount is different between states and will sometimes
change over time and the user should be allowed to edit the amount to suit his/her
needs. At the very least, the assumed default value for a particular state should be
displayed clearly.
3. The savings in CO2 emission of performing each individual upgrade is not displayed.
This would be valuable to users who want to get a feel for how each upgrade affects
their CO2 emissions, and those who are attempting to maximize their emission
reduction per dollar invested.
4. The calculator does not show the formulas and assumptions used to arrive at the
numbers calculated. The inclusion of that would greatly increase the confidence of the
more scientifically-trained users (such as engineer homeowners) in the results.
Documentation on the HES [HES07] attempts to serve this purpose but it is a long,
complex document that is not easily accessible without a fair bit of searching.
38
5. The ‘Typical Costs’ listed for many of the upgrades (figure 2-15) are listed as the
incremental cost of upgrading to an efficient unit over a new non-efficient unit. This is
a fair cost to use when calculating, say, the return on investment of replacing a unit
that has to be replaced because it is no longer functional. In this case, the only
decision to be made is whether to purchase a pricier energy-efficient unit or a cheaper
inefficient unit and thus it is important to know what the return is on the incremental
cost of the efficient unit from the reduction in energy costs. However, if the current old
inefficient unit is still operational and does not need replacement, it is only fair to
calculate the return on investment on the whole price of a new efficient unit.
39
2.4 CO2 Emissions
Carbon dioxide (CO2) is one of the gases that have been identified as a greenhouse gas
(GHG). A GHG is a gas that leads to the warming of the earth’s atmosphere through a global
phenomenon termed the greenhouse effect. In this phenomenon, the sun’s radiant energy
enters the earth’s atmosphere as short-wavelength radiation, is reflected or is re-radiated by
the earth’s surface as long-wavelength radiation which is absorbed by GHGs present in the
earth’s atmosphere causing the temperature of the earth’s atmosphere to rise. The rise in the
earth’s atmosphere has been shown to be linked to some drastic effects on natural
environments. The Intergovernmental Panel on Climate Change (IPCC) claims that snow and
ice have melted, sea levels have risen, ocean salinity patterns have changed, and more
severe droughts and intense tropical cyclones have occurred [IPCC07]. The presentation of
such scientific findings and the recent publicity of global warming by famous advocated such
as Nobel-prize winner and former US vice-president Al Gore has led to global warming
becoming a major issue in the public conscience. Moreover, the increase of man-made CO2
leading to increased global warming has become a very popular topic leading to governments
around the world pledging to reduce their carbon emissions. There are two major control
mechanisms that are considered by governments to control and ultimately reduce their
country’s CO2 emissions: carbon tax and the cap and trade system.
A carbon tax is a tax that is levied on the amount of CO2 emitted by any activity. It is usually
implemented as a revenue neutral tax, meaning that revenue collected from the tax is used to
fund activities that further help reduce CO2 emissions, such as rebates on bicycles or grants
for renewable energy power stations. The aim of the tax is to put a price on the emission of
every tonne of CO2 so as to provide a financial incentive for polluting entities to cut down on
their emissions. It makes it easier for profit-seeking corporations to invest in technologies
that would reduce their CO2 emissions because the pay-off of investing in such technologies
40
from the savings in carbon tax payment could be far greater than the initial investment
required.
Under the cap and trade system, the idea of incentivizing entities to reduce their carbon
emissions by charging them for their emissions is as much part of the core philosophy as
under the carbon tax strategy, however, the price levied on CO2 emissions is not set by the
government. The price is in fact left to be determined by the free market through the
interaction of the forces of demand and supply. On a very basic level, a limited number of
carbon credits are sold on the open market and these credits are bought by corporations to
give them the right to emit the amount of CO2 represented by the credits. Then, if a
corporation is able to reduce its emissions over time (through investments in technology or
other innovations) the corporation may sell these carbon credits on the open market as it will
have no need for the extra credits. This sale will generate revenue for the corporation thus
providing the profit motive required for it to invest in emission reduction strategies. The
carbon credits are envisioned to be traded just like securities are currently traded.
To give an idea of how polluting different sources of energy are CO2 emission factors for some
of them are given in table 2-9. The CO2 emission factor is the amount of CO2 emitted per unit
of fuel. It is interesting to note the varying amounts of emissions for the different fuels listed.
Amongst the non-electric sources of energy it can be seen that natural gas emits the least
and coal emits the most CO2 per GJ of energy content in the fuel. In Canada, electricity is
generated in different provinces using quite different sources of energy (hydro, nuclear, wind,
gas, coal, oil, etc.) and since all these sources emit different amounts of carbon per unit of
energy (some like wind do not produce any emissions) the emission factors for electricity
generated in the different provinces can be quite different as shown in the table. It can be
seen that Quebec’s electricity is the least polluting and Alberta’s is the most polluting at about
150 times that of Quebec. It should be noted, however, that the carbon emission levels
41
arising from the construction and maintenance of these generating methods are not
accounted for in these figures.
Table 2-10 CO2 emission factors
Fuel Source CO2 Emission Factor
Emission per energy
content (kg/GJ)
Natural Gas 1.891 kg/m3 51.0 Ethane 0.976 kg/L 53.2 Propane 1.510 kg/L 59.1 Butane 1.730 kg/L 60.4 Ethanol 1.484 kg/L 62.9 Gasoline 2.289 kg/L 66.0 Diesel 2.663 kg/L 68.8 Light Fuel Oil 2.725 kg/L 70.4 Heavy Fuel Oil 3.124 kg/L 74.9 Coal 2.3 kg/kg 83.0 Electricity - QB 0.006 kg/kWh 1.7 Electricity - MN 0.010 kg/kWh 2.8 Electricity - NFL & LB 0.015 kg/kWh 4.2 Electricity - BC 0.020 kg/kWh 5.6 Electricity - YK, NWT, & NU 0.080 kg/kWh 22.2 Electricity - ON 0.180 kg/kWh 50.0 Electricity - PEI 0.192 kg/kWh 53.3 Electricity - Canada 0.205 kg/kWh 56.9 Electricity - NB 0.366 kg/kWh 101.7 Electricity - NS 0.549 kg/kWh 152.5 Electricity - SK 0.810 kg/kWh 225.0 Electricity - AL 0.930 kg/kWh 258.3
Source: Environment Canada, http://www.ec.gc.ca/pdb/ghg/inventory_report/2005_report/a12_eng.cfm#a12 and http://www.ec.gc.ca/pdb/ghg/inventory_report/2006_report/a9_eng.cfm
42
2.5 Incentive Programs in Canada
Incentive programs aimed at subsidizing the cost of upgrading to more energy efficient
systems are plentiful in Canada. They are provided by the federal, provincial and sometimes
even municipal governments. A popular federal government program is known as ecoENERGY
Retrofit and provincial ones have names such as Home Energy Ontario and Conserve Nova
Scotia. This section shows the characteristics of some of these programs.
The existence ecoENERGY Retrofit is rationalized in recent press releases by citing the
program’s positive effect on job creation and protection in the construction and home
renovation industry [ERPR]. Also citied is its ability to stimulate the economy since it is
expected that Canadian homeowners will spend 10 times as much as the government will on
energy conservation products (since the grants only cover a fraction of the capital cost)
leading to $2.4 billion of economic activity [ERPR]. Additionally, it can be argued that since
the program aims at reducing Canada’s consumption of energy (through better energy
efficiency) the program can reduce pressure on public facilities such as power generators and
water treatment plants to increase capacity. These are appropriate economic reasons to
justify the cost of the program to the government. Of course, the non-economic and more
well-known reason for the program’s existence is that it helps to reduce Canada’s greenhouse
gas emissions by aiming to reduce Canada’s energy consumption.
To gain a sense of the characteristics of an incentive program, the ecoENERGY Retrofit
program is analyzed. This program provides a maximum of $5,000 for energy-conservation
renovations of low-rise residential properties [ER25]. These properties are defined to include
single detached and attached homes, multi-unit residential building of three storeys or less
with a maximum footprint area of 600 m2, and mobile and floating homes that are
permanently attached to a foundation [OEERET]. The types of system upgrades eligible for
the grant include space heating, space cooling, ventilation, water heating, building insulation,
43
fenestration, water conservation systems [ERGRANT]. The process of obtaining the grant
involves the following four main steps [ERSTEPS]:
• Hire a Natural Resources Canada certified energy advisor to produce a pre-retrofit
evaluation report of the dwelling
• Perform the recommended upgrades within the time limit (18 months)
• Call the certified energy advisor for a post-retrofit evaluation
• Submit a grant application with the pre- and post-retrofit evaluations to receive the
grant within 90 days
Table 2-10 gives a sample of the incentives available from ecoENERGY Retrofit. The complete
list of upgrades is available at [ERGRANT]. Table 2-11 is a similar table that shows programs
available at the provincial level. It can be seen that the dollar amounts of these incentives
vary greatly.
The available incentive programs change over time, in addition to varying greatly in the
amount of incentives provided, types of upgrades eligible, the process of receiving the grant.
For example, on March 29, 2009 ecoENERGY Retrofit grants increased by 25% for a limited
time [ER25]. It is evident that creating a database of all incentive programs available in
Canada is quite a labour intensive effort in the first place, but keeping this database updated
is a continuous and perpetual process. Interestingly, there is list of numerous Canadian
programs available from Environment Canada at [ECINCT]. The FSI may be interested in
including a link to this page on their calculator to inform users of such incentives.
44
Table 2-11 Federal government grants and incentive programs – ecoENERGY Retrofit
Type of Upgrade Specific Upgrade
Grant amount for single-
family home
Heating system
Replace current system with ENERGY STAR qualified gas furnace that has a 92.0% AFUE or higher and a brushless DC motor
$625
Cooling system
Replace your window air conditioner(s) with an ENERGY STAR qualified unit(s) (per unit replaced; maximum of 5 units)
$25
Building envelope insulation
Increase the insulation value of your attic (of R-12 or less) to achieve a total minimum insulation value of RSI 8.8 (R-50)
$750
Water heating system
Replace your domestic hot water heater with an ENERGY STAR qualified instantaneous, gas-fired water heater that has an energy factor (EF) of 0.82 or higher and is on the ecoENERGY Retrofit – Homes list of eligible domestic hot water heaters
$315
Fenestration Replace windows and skylights with models that are ENERGY STAR qualified for your climate zone. (per unit replaced)
$40
Source: Natural Resources Canada, http://www.oee.nrcan.gc.ca/residential/personal/retrofit-homes/retrofit-qualify-grant.cfm?attr=4
45
Table 2-12 Provincial grants and incentive programs
Province Program Name [Website] Sponsor Sample Incentive
Sample Incentive Amount
Alberta Carbon Dioxide Reduction Edmonton (CO2RE)
[http://www.edmonton.ca/environmental/documents/Low_Income_FAQ_-_2009-02-05.pdf]
Residential Rehabilitation
Assistance Program
Rebate on installation high-efficiency gas
furnace for low-income households
$2,000
British Columbia SmartWash Rebate Program
[http://www.crd.bc.ca/water/conservation/rebates/smartwash.htm]
Capital Regional District, City of
Vancouver
Rebate on installation of high-efficiency clothes
washing machine
$100
British Columbia LiveSmart BC: Efficiency Incentive Initiative
[http://www.fortisbc.com/powersense/upgrading_existing_home.html]
FortisBC, Province of BC, federal government
Heat pump rebate (rebate function of
energy saving, in kWh)
$0.05 per kWh
Manitoba PowerSmart Furnace/Boiler Replacement
[http://www.hydro.mb.ca/your_home/furnace_replacement_program.shtml]
Manitoba Hydro Replace old furnace or boiler (rebate) $245
New Brunswick Existing Homes Energy Efficiency Upgrades [http://www.efficiencynb.ca/enb/1600/Residential]
Efficiency New Brunswick
Subsidize cost of NRCan energy assessment
service $400
Nova Scotia Conserve Nova Scotia [http://www.conservens.ca/rebates/]
Government of Nova Scotia
% rebate on the total installed cost of a solar
air or water heating system
15% (Max $20,000)
Ontario Home Energy Ontario [http://www.homeenergyontario.ca/index.asp]
Government of Ontario
Same rebates as ecoACTION. Doubles
maximum grant amount available
Max $10,000
Quebec Gaz Metro High-efficiency Hot Air Furnace
[http://www.gazmetro.com/residentielactuel/efficaciteenergetique/en/html/652820_en.aspx?culture=en-CA]
Gaz Metro Rebate on replacement of furnace $450
46
2.6 Net Present Value
The net present value (NPV) of an investment gives the true monetary cost or benefit of
implementing a project over the life of the project by aggregating all the costs and benefits
incurred over the project’s time horizon. The NPV model discounts future cash flows (as
demonstrated below) to account for the time value of money and as such it is also referred to
as a discounted cash flow model. The time value of money is an important concept in
economics which formalizes the idea that money earned (or saved) today is worth (or valued)
more than the same amount of money earned a year from today because money earned today
can be invested to produce a larger sum of money a year later. For example, it can be noted
that given the option of receiving $100 today or $100 a year from today, and given that money
can be invested in a risk-free bond (or savings account) at a rate of say 3% per year, it would
be more beneficial to choose the former because the $100 received today can be invested to
receive a sum of $103 a year from now, which is worth more than the option of receiving only
$100 a year from now. Similarly, the value of money earned in the future (also known as
“future cash flow”) is actually smaller than the same amount of money earned today. Hence, all
future cash flows have to be “discounted” to determine their value on today’s date.
Generally, most upgrade projects have the same elements organized in a logically structured
manner for calculating their NPV. These elements are the First Cost, Annual Savings, interest
rate, and the project life. First, some initial investment has to be made to upgrade the
equipment (such as the price and installation cost of putting in a higher efficiency furnace, a
programmable thermostat, or a high-efficiency bulb). This initial investment is referred to as
the First Cost (FC) and it occurs right at the start of the project. Figure 2-16 shows what is
called a Cash Flow Diagram and it gives a graphical representation of all cash flows that occur
during the life of the project. Costs incurred are represented by downward pointing arrows, and
savings/revenues generated by the project are represented by upward pointing arrows. Each
47
cash flow arrow is drawn at the time the cash flow is actually incurred in the project. Hence, the
FC is drawn as a downward arrow because it is a cost and at year 0 which represents the start
of the project.
Figure 2-16 Cash Flow Diagram
Second, the Annual Saving (AS) is the dollar amount that is saved from the operations of the
project every year. In the case of replacing a furnace with a high-efficiency model, the AS is the
saving in the annual heating bill achieved as a result of reducing the amount of heating fuel
consumed since the high-efficiency furnace is able to deliver more heat to the house per
quantity of fuel burned. The AS can be expected to increase year-over-year as the price of
energy increases even though the quantity of energy saved is expected to stay constant. Figure
2-17 shows how the price of energy has changed in Canada from 1961 to 2007 [OECD09]. It
plots the consumer price index (CPI) for energy and for a basket of goods (referred to as “CPI
All Items”) as reported for Canada by the Organisation for Economic Co-Operation and
Development (OECD) Factbook 2009. It can be seen from this plot that not only has the price of
energy historically increased year-over-year, but that it has increased a faster rate than CPI All
Items (a measure of general inflation). The AS is also expected to occur every year until the
Time (years)
0 1 2 3 4 5 N-1 N
FC
AS AS AS
AS
AS
AS
AS
48
end of the life of the project (N years). The life of the project is the number of years that the
new installation (high-efficiency furnace, bulb, etc.) is expected to give the benefit it was
intended to. The AS is drawn as upwards arrows at the end of every year until year N on the
cash flow diagram.
y = 100e0.0566x
R2 = 0.93
y = 10x + 70R2 = 0.99
100
300
500
700
900
1100
1300
1500
0 10 20 30 40 50
Years after 1961
Pric
e In
dex
CPI All ItemsCPI EnergyFit (CPI Energy)Fit (CPI All Items)
Figure 2-17 Consumer Price Indices for Canada from 1961 to 2007
To calculate the NPV of an upgrade project, the future cash flows, i.e. the annual savings, have
to be discounted over the years using the interest rate i to determine their actual value at the
start of the project. In their book, Engineering Economics in Canada, Fraser et al. [FRAS06]
give the formulation for determining the cumulative present value (PV) of all the annual savings
from the start to the end of the project as the following, where AS, i, and N are as defined in
the preceding discussion. Using the terminology used in the book, the AS amounts in this
49
particular case form a geometric gradient series with g being defined as the growth rate for the
geometric gradient.
PV = A x (P/A,g,i,N) =gii
iAN
N
+⎥⎥⎦
⎤
⎢⎢⎣
⎡
°+°
−°+×
11
)1(1)1(
Where °i is defined as the growth adjusted interest rate:
111
−++
=°gii
The growth rate here is the annual percentage change in energy prices which can be obtained
from figure 2-17. It can be seen that the CPI Energy data points can be approximated by an
exponential function with a good fit (R2 values of about 0.93). Whereas, the CPI All Items data
points are best approximated by a linear function (R2 value of 0.99) and this type of price
growth is referred to as an arithmetic gradient series in Engineering Economics in Canada
[FRAS06]. An arithmetic gradient series eventually grow slower than geometric ones as can be
seen in figure 2-17 since the CPI Energy plot overtakes the CPI All Items one.
From the equation of the approximating exponential function it is possible to calculate the
average annual percentage change g in prices:
1. Consider a general exponential function y = 100eax
2. Take two consecutive points (y1,x1) and (y2,x2) on the exponential function such that
x2 – x1 = 1 year and x2 > x1.
3. Since y2 and y1 approximate the CPIs for year x2 and x1 respectively, the average
annual percentage change in prices can be defined by:
% change = 1
12y
yy −
4. Then: % change = 1
12
100100100
112
ax
axax
eee
yyy −
=− where a is the exponent number of the
fit function.
50
5. Simplifying: % change = 1
12
ax
axax
eee − = 1
1
2−
ax
ax
ee = 12)( xxae − - 1
6. Since x2 – x1 = 1, then:
% change = ea - 1
Therefore the average annual percentage change for CPI Energy is e0.0566 - 1 = 5.82%. For the
purposes of our calculations we can use g = 5.82% to calculate the PV in the aforementioned
equation. It can be seen that since this price growth rate g is approximated from data over
about the last 50 years it will serve as a valid estimate for the future period of 10 -18 years
that are used in the calculations in chapter 3 because the pattern of growth is not likely to
change drastically.
The net present value (NPV) of the whole project is just the sum of the PV of all the savings and
the FC. The FC does not need to be discounted because it not a future cash flow. However, the
FC is a cost and so lowers the NPV of the project and thus has a negative sign.
FCNPV −= + A x (P/A,g,i,N)
Finally, for the sake of completeness it should be noted that some installations may attract a
salvage cost if there are residual environmental concerns. An example of this could be a high
efficiency oil furnace whose fuel tank may have to be disposed of as a toxic material.
51
Chapter 3 Financial & Environmental Implication of Energy Savings
This section present models that will be used by the FSI in the algorithm of their calculator. All
of the sections are presented in the same general format. First, the logic of the calculation
procedure is explained, and the source of this logic is noted. Then, the questions to be asked
are presented and an explanation of how the user would obtain the information prompted for by
the question. Next, the algorithm for the calculation is given along with the definitions of terms
used in the algorithm. Finally, a sample calculation is presented for a set of arbitrary sample
answers to the input questions.
The algorithms all rely on some common data tables shown below and described here. Table 3-
1 is a compilation of typical energy prices in 2008 for all of the Canadian Provinces. Electricity,
natural gas, and heating oil prices are included. The source of all the prices is also included.
Table 3-2 shows the CO2 emission level for electricity usage in all Canadian Provinces. Table 3-3
shows the average life expectancy of various equipment sourced from a study commissioned by
the Bank of America and conducted by the National Association of Home Builders (NAHB).
52
Table 3-1 Typical energy prices by provinces
Province Electricity Price ($/kWh)
Natural Gas Price ($/m3) Heating Oil Price ($/L)
NFL & LB -- -- 0.85 PEI 0.107 -- 0.71 NS 0.110 0.18 0.77 NB -- -- 0.85 QB 0.053 0.43 [2] 0.84 ON 0.078 [1] 0.35 [3] 0.84 MN 0.059 0.31 -- SK 0.095 0.27 -- AL 0.100 0.22 -- BC 0.065 0.96 [4] 0.93 YK -- -- --
NWT 0.110 -- -- NU -- -- --
-- means data was not available
Source of prices:
All unlabelled prices: Centre For Energy, Available at:
http://www.centreforenergy.com/FactsStats/Statistics.asp?Template=5,1 [1] Energyshop.com, Available at: http://www.energyshop.com/es/prices/ON/eleON.cfm?ldc_id=293& [2] Gaz Metro, Available at: http://www.grandeentreprise.gazmetro.com/data/media/VGE%20D4%20-
%20d%C3%A9c%202008%20-%20anglais.pdf [3] Direct Energy, Available at:
http://www.directenergy.com/EN/Ontario/RES/Pages/GAS/NaturalGasDefault.aspx?PostalZipCode=Z
1Z1Z2&Business=RES&Commodity=GAS&Language=EN&ProvState=ON [4] Terasen Gas, Available at: http://www.terasengas.com/Homes/Rates/Whistler.htm
Table 3-2 CO2 emission for electricity by provinces
Province 2006 Level* (kgCO2/kWh)
Canada 0.205 NFL & LB 0.015
PEI 0.192 NS 0.549 NB 0.366 QB 0.006 ON 0.180 MN 0.010 SK 0.810 AL 0.930 BC 0.020
YK, NWT, & NU 0.080 Source: http://www.ec.gc.ca/pdb/ghg/inventory_report/2006_report/a9_eng.cfm
53
Table 3-3 Average life expectancy of equipments
Equipment Life Expectancy (years) Furnace – Gas 18 Furnace - Oil 20 Heat Pump 16 Thermostat 35
Window 10 Insulation Lifetime
Refrigerator – Compact 9 Refrigerator – Standard 13
Source: National Association of Home Builders, http://www.nahb.org/fileUpload_details.aspx?contentID=72475
54
3.1 Upgrading Furnace Efficiency
The installation of a new furnace with a higher efficiency is considered here. It is assumed that
the current furnace will be disconnected from its connections to air ducts, vents, drains, and
fuel supply lines and the new furnace will be connected in its place. Thus, from the point of view
of energy consumption and CO2 emission calculation, the only difference between the new and
the current system is the annual fuel usage efficiency (AFUE) and it is this change in AFUE that
is used to calculate the savings in heating fuel. This procedure can be used for gas or oil
burning furnaces. The procedure used here is based on the Energy Star’s Life Cycle Cost
Estimate for an ENERGY STAR Qualified Oil/Gas Residential Furnace found on the American
Energy Star’s website [FURN].
The saving in heating fuel is calculated as follows: Multiplying the current annual consumption
of heating fuel used for space heating with heat energy content of a unit of heating fuel gives
heat energy input to the current furnace. Further multiplying this product with the AFUE of the
current furnace gives the heat energy output of the current furnace. This is also the annual
heat energy requirement of the dwelling which is independent of the type or efficiency of the
heating system used. Thus, the annual consumption of heating fuel used for space heating
purposes for the new system can be calculated by dividing the annual heat energy requirement
by the new AFUE and the heat energy content of a unit of heating fuel. The saving in heating
fuel is then the difference between the current annual consumption and the calculated new
annual consumption.
Next, the CO2 emission savings (or reductions) of this project can be calculated as follows:
Simply multiplying the saving in heating fuel by the CO2 emission factor for the heating fuel
(1.89 kg/m3 for natural gas and 3.124 kg/L for heating oil) gives annual CO2 saving. Then the
55
total lifetime CO2 saving is calculated by multiplying this annual saving with the expected life (in
years) of the new furnace.
Finally, the financial implications of this project can be calculated as follows: The annual dollar
saving from the saving in heating fuel is calculated by multiplying the heating fuel saving
amount by the unit price of the heating fuel. There is also a possible annual dollar saving from
the CO2 emission saving that can be calculated by multiplying the annual CO2 saving with the
unit price of CO2 emissions. If there is no price placed on CO2 emissions then this annual dollar
saving falls to zero. Next, the total annual dollar saving is the sum of these two annual dollar
savings. Finally, the net present value of the project is calculated by subtracting the first cost of
the new furnace from the present value of the all the annual dollar savings over the life of the
project discounted at the user-provided interest rate.
Algorithm
As for all the following sections, a table listing the questions to be used to elicit input from the
user is included before the algorithm. The last column of the table entitled ‘Defaulted?’ shows if
that particular question can be answered by default using other user inputs. These defaulted
questions will be displayed with the input value filled in with the default values giving users the
opportunity to change the input value to better suit their particular situation.
# Variable Input Questions Units Defaulted? 1 PROV What province do you live in? -- 2 HF What heating fuel does your furnace use? (NG/HO) --
HF = NG m3/year 3 ACHF_C Current: Annual HF consumption for
space heating HF = HO L/year
4 AFUEC AFUE of Current % 5 AFUEN AFUE of New %
HF = NG kg/m3 6 CO2EMHF Emission factor for HF heating fuel HF = HO kg/L
7 LY Life years HF = HO kg/L 8
PHF Price of heating fuel HF = HO $/L
9 FC First cost of new furnace $
56
10 i Interest rate % 11 g Average annual rate of growth in energy prices % 12 PCO2 Price of CO2 emission $/1000kg
NG = natural gas HO = heating oil
In the algorithms for all sections the input variables (those that are populated by the user’s
answers) are bolded. All other non-bolded variables are calculated from the bolded input
variables as shown by the algorithm and their definition is given in the tables following the
algorithms.
Set defaults: LY to LY_DEF, CO2EMHF to CO2EMHF_DEF(HF),
PHF to PHF_DEF(HF, PROV), i to i_DEF, g to g_DEF, PCO2 to PCO2_DEF
HER = ACHF_C x AFUEC x HEHF(HF)
ACHF_N = HER ÷ AFUEN ÷ HEHF(HF)
HFS = ACHF_C – ACHF_N
CO2SAVHF = HFS x CO2EMHF
L_CO2SAV = CO2SAVHF x LY
ADSHF = HFS x PHF
ADSCO2 = CO2SAVHF ÷ 1000 x PCO2
ADSTOT = ADSHF + ADSCO2
°i = (1+i)÷(1+g) - 1
NPV = -FC + ADSTOT x (P/A, g, °i , LY)
Variable Definition Units Value of Constant
LY_DEF Default value for life of new furnace Years Table 3-3 HF = NG kg/m3 1.89 CO2EMHF_
DEF (HF) Default value for emission factor for HF HF = HO kg/L 3.124 HF = NG $/m3 PHF_DEF
(HF, PROV)
Default value for price of HF in PROV province: Lookup from Table 3-1 HF = HO $/L
Table 3-1
i_DEF Default value for interest rate % 4.00* g_DEF Default value for annual rate of growth in energy prices % 5.82 PCO2_DEF Default value for price of CO2 emission $/1000kg 0 HER Heat energy requirement of dwelling (annual) kBTU/year --
HF = NG kBTU/m3 35.5 HEHF(HF) Heat energy of HF heating fuel HF = HO kBTU/L 39.6
57
HF = NG m3/year ACHF_N Annual HF consumption of new system HF = HO L/year
--
HF = NG m3/year HFS Heating fuel saving HF = HO L/year
--
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year -- L_CO2SAV Total saving in CO2 emission over lifetime of new furnace kg -- ADSHF Annual dollar saving from reduction in HF consumption $/year -- ADSCO2 Annual dollar saving from reduction in CO2 emission $/year -- ADSTOT Total annual dollar saving $/year -- °i Growth adjusted interest rate % --
NPV Net present value $ -- * Default value for the interest rate is best set by the FSI, 4.00% is just an arbitrary example.
Notes on Input Questions
Some questions such as those represented by the PROV and HF variable are straightforward to
answer. Others are listed below with explanations as to how users will answer the asked
questions:
ACHF_C This can be calculated by the user by multiplying the average of fuel usage amounts
from a few months of heating fuel bills from the non-heating months by 12 and
subtracting that from the sum total of fuel usage amounts from monthly heating fuel
bills of 12 consecutive bills.
AFUEC The AFUE of the current furnace may be obtained from the product datasheet if
available, the information plate on the back of the furnace, or table 3-4 which gives
the average AFUE of all furnaces shipped in a specified year, sourced from the
documentation for the Home Energy Saver calculator [HES07].
AFUEN The AFUE of a new furnace is provided by the manufacturer in the product datasheet
and is usually displayed conspicuously by retailers.
CO2EMHF The emission factor is only dependant on the heating fuel used. It does not vary from
province to province since heating fuel such as natural gas or heating oil always emit
the same amount of CO2 when combusted no matter where. It is defaulted to values
as shown in the variable definition table given after the algorithm.
PHF This can be obtained from the user’s heating fuel bills. It can be defaulted to a value
from table 5-1 based on the heating fuel used and the province specified.
FC The first cost should the sum total of the price of the new furnace, installation costs,
transportation costs, grants, rebates, and all applicable taxes.
58
i The interest rate is very specific to the users and depends on their source of
financing. It can be defaulted to some function of the current prime interest rate.
g Defaulted rate calculated from fit to CPI Energy.
PCO2 This optional price of CO2 emission is put in to give users the ability to view the effect
of future prices. It is presently defaulted to 0 since there currently is no tax on CO2
emission in provinces.
Table 3-4 Shipment weighted AFUE for heating systems by year of shipment
Source: Home Energy Saver calculator documentation [HES07]
59
Sample Calculation
This sample calculation shows how the algorithm will be used to calculate the outputs using the
sample inputs shown in the table below.
# Variable Input Questions Units Sample Input 1 PROV What province do you live in? -- ON 2 HF What heating fuel does your furnace use? -- NG
3 ACHF_C Current: Annual HF consumption for space heating HF = NG m3/year 3,000
4 AFUEC AFUE of Current % 80% 5 AFUEN AFUE of New % 95% 6 CO2EMHF Emission factor for HF heating fuel HF = NG kg/m3 1.89 7 LY Life years 18 8 PHF Price of heating fuel $/m3 0.30 9 FC First cost of new furnace $ 1,300.00 10 i Interest rate % 4.00 11 g Average annual rate of growth in energy prices % 5.82 12 PCO2 Price of CO2 emission $/1000kg 0
HER = ACHF_C x AFUEC x HEHF(HF) = 3,000 x 80% x 35.5 = 85,200 kBTU/year
ACHF_N = HER ÷ AFUEN ÷ HEHF(HF) = 85,200 ÷ 95% ÷ 35.5 = 2,526.32 m3/year
HFS = ACHF_C – ACHF_N = 3,000 - 2,526.32 = 473.68 m3/year
CO2SAVHF = HFS x CO2EMHF = 473.68 x 1.89 = 895.26 kg/year
L_CO2SAV = CO2SAVHF x LY= 895.26 x 18 = 16,114.74 kg
ADSHF = HFS x PHF = 473.68 x 0.30 = $142.10/year
ADSCO2 = CO2SAVHF ÷ 1000 x PCO2 = 895.26 ÷ 1000 x 0 = 0
ADSTOT = ADSHF + ADSCO2 = 142.10 + 0 = $142.10/year
°i = (1+i)÷(1+g) - 1 = (1+0.04)÷(1+0.0582) - 1 = -0.0172 = -1.72%
NPV = -FC + ADSTOT x (P/A, g, °i , LY) = -1,300+142.10x(P/A,5.82%,-1.72%,18) = $1,561.87
60
3.2 Upgrading Heat Pump Efficiency
The installation of a new high efficiency heat pump to either upgrade an existing heat pump or
to replace a fuel burning furnace is considered here. When upgrading from an existing heat
pump, it is assumed that the current heat pump will be disconnected from its connections to air
ducts, heating fluid, and power lines and the new heat pump will be connected in its place.
Thus, from the point of view of energy consumption and CO2 emission calculation, the only
difference between the new and the current system is the coefficient of performance (HCOP)
and it is this change in HCOP that is used to calculate the saving in heating fuel. The calculation
procedure used here is based on the Energy Star’s Air-Source Heat Pump(s) and Ground Source
Heat Pump(s) found on the Canadian Energy Star’s website [ESCAN].
When upgrading an existing heat pump the saving in electricity is calculated as follows:
Multiplying the current annual consumption of electricity used for space heating with the
current heat pump’s HCOP gives the heat energy output of the current heat pump. This is also
the annual heat energy requirement of the dwelling which is independent of the type or
efficiency of the heating system used. Thus, the annual consumption of electricity used for
space heating purposes for the new system can be calculated by dividing the annual heat
energy requirement by the new HCOP. The saving in heating electricity is then the difference
between the current annual consumption and the calculated new annual consumption. The
savings in CO2 emissions, and the net present value of the project are calculated in quite the
same manner as previously done for the case of the furnace.
On the other hand, for the option of replacing a furnace with a new heat pump the calculation
initiates similar to that for upgrading a furnace considered in the last section. The heat energy
requirement is calculated as before, but then the annual electricity consumption for the new
heat pump is calculated using this heat energy requirement. The saving in CO2 emission is
61
calculated by taking the difference between the emission in operating the current furnace and
the new heat pump, utilizing CO2 emission factors of electricity and the heating fuel for the heat
pump and the furnace respectively. The annual dollar saving is also calculated as the difference
in the cost of heating fuel and electricity required to operate the two heating systems.
Algorithm
# Term Input Questions Units Defaulted? 1 PROV What province do you live in? --
2 HSYSC What is your current heating system? (Furnace OR Heat Pump) --
3A-1 HF What heating fuel does your furnace use? (NG/HO) --
HF = NG m3/year 3A-2 ACHF_C Current: Annual HF consumption
for space heating HF = HO L/year
3A-3 AFUEC AFUE of current furnace % HF = NG kg/m3 3A-4 CO2EMHF Emission factor for HF heating fuel HF = HO kg/L
3A-5 PHF Price of heating fuel HF = HO kg/L 3B-1 ACEL_C Annual electricity consumption for heating kWh/year 3B-2 HCOPC Heating COP – current system -- 3B-3 CO2EMEL Emission factor for EL for PROV province kg/kWh 3B-4 PEL Price of electricity (EL) $/kWh
4 HCOPN Heating COP – NEW heat pump -- 5 LY Life of new heat pump years 6 FC First cost $ 7 i Interest rate % 8 g Average annual rate of growth in energy prices % 9 PCO2 Price of CO2 emission $/1000kg
Set defaults: CO2EMHF to CO2EMHF_DEF(HF), PHF to PHF_DEF(HF, PROV),
CO2EMEL to CO2EMEL_DEF(PROV), LY to LY_DEF, PEL to PEL_DEF(PROV),
i to i_DEF, PCO2 to PCO2_DEF
IF HSYSC = Furnace THEN
Ask HF <3A-1>, ACHF_C <3A-2>, AFUEC <3A-3>, CO2EMHF<3A-4>, PHF<3A-5>
HER = ACHF_C x AFUEC x HEHF(HF) ÷ CONVFkBTU/kWh
ACEL_N = HER ÷ HCOPN
CO2SAV = ACHF_C x CO2EMHF - ACEL_N x CO2EMEL
62
ADSHC = ACHF_C x PHF - ACEL_N x PEL
ELSE
Ask ACEL_C<3B-1>, HCOPC<3B-2>, CO2EMEL<3B-3>, PEL<3B-4>
HER = ACEL_C x HCOPC
ACEL_N = HER ÷ HCOPN
CO2SAV = (ACEL_C - ACEL_N) x CO2EMEL
ADSHC = (ACEL_C - ACEL_N) x PEL
END IF
L_CO2SAV = CO2SAV x LY
ADSCO2 = CO2SAV÷ 1000 x PCO2
ADSTOT = ADSHC + ADSCO2
°i = (1+i)÷(1+g) - 1
NPV = -FC + ADSTOT x (P/A, g, °i , LY)
Term Definition Units Value of Constant
HF = NG kg/m3 1.89 CO2EMHF_DEF (HF) Default value for emission factor for HF
HF = HO kg/L 3.124 HF = NG $/m3 PHF_DEF
(HF, PROV) Default value for price of HF in PROV province: Lookup from Table 3-1 HF = HO $/L
Table 3-1
CO2EMEL_DEF (PROV)
Default value for emission factor for EL for PROV province: Lookup from table 3-2 kg/kWh Table 3-2
LY_DEF Default value for life if new heat pump Years Table 3-3 PEL_DEF (PROV)
Default value for price of EL in PROV province: Lookup from table 3-1 $/kWh Table 3-1
i_DEF Default value for interest rate % 4.00 PCO2_DEF Default value for price of CO2 emission $/1000kg 0 HER Heat energy requirement of dwelling (annual) kWh/year -- CONVFkBTU/kWh Conversion factor: kWh to kBTU kBTU/kWh 3.4
HF = NG kBTU/m3 35.5 HEHF(HF) Heat energy of HF heating fuel HF = HO kBTU/L 39.6
ACEL_N Annual EL consumption of new system kWh/year -- HES Heating EL saving kWh/year -- CO2SAV Saving in CO2 emission kg/year -- CO2EMEL
(PROV) Emission factor for EL for PROV province kg/kWh --
L_CO2SAV Total saving in CO2 emission over lifetime of new heat pump kg --
ADSHC Annual dollar saving from reduction in heating costs $/year -- ADSCO2 Annual dollar saving from reduction in CO2 emission $/year --
63
ADSTOT Total annual dollar saving $/year -- NPV Net present value $ --
Notes on Input Questions
ACEL_C This can be measured by installing an energy meter on the power cable supplying the
heat pump.
HCOPC The heating COP of the current heat pump may be obtained from the product
datasheet if available, the information plate on the back of the heat pump, or table
3-4
HCOPN The heating COP of a new heat pump is provided by the manufacturer in the product
datasheet and is usually displayed conspicuously by retailers.
CO2EMHF The emission factor is only dependant on the heating fuel used. It does not vary from
province to province. It is defaulted to values as shown in the variable table after the
algorithm.
PEL This can be obtained from the users’ electricity bills. It can defaulted to a value from
table 3-1 based on the province specified.
64
Sample Calculation
# Term Input Questions Units Sample Input 1 PROV What province do you live in? -- QB
2 HSYSC What is your current heating system? (Furnace OR Heat Pump) -- Heat Pump
3B-1 ACEL_C Annual electricity consumption for heating kWh/year 10,000 3B-2 HCOPC Heating COP – current system -- 3.0 3B-3 CO2EMEL Emission factor for EL for PROV province kg/kWh 0.006 3B-4 PEL Price of electricity (EL) $/kWh 0.053
4 HCOPN Heating COP – NEW heat pump -- 5.0 5 LY Life of new heat pump years 15 6 FC First cost $ $4000 7 i Interest rate % 4% 8 g Average annual rate of growth in energy prices % 5.82 9 PCO2 Price of CO2 emission $/1000kg 0
IF HSYSC = Furnace THEN …
ELSE
Ask ACEL_C<3B-1>, HCOPC<3B-2>, CO2EMEL<3B-3>, PEL<3B-4>
HER = ACEL_C x HCOPC = 10,000 x 3.0 = 30,000 kWh/year
ACEL_N = HER ÷ HCOPN = 30,000 ÷ 5.0 = 6,000 kWh/year
CO2SAV = (ACEL_C - ACEL_N) x CO2EMEL = (10,000 – 6,000) x 0.006 = 24 kg/year
ADSHC = (ACEL_C - ACEL_N) x PEL = (10,000 – 6,000) x 0.053 = $212/year
END IF
L_CO2SAV = CO2SAV x LY = 24 x 15 = 360 kg
ADSCO2 = CO2SAV÷ 1000 x PCO2 = 36 ÷ 1000 x 0 = 0
ADSTOT = ADSHC + ADSCO2 = 212 + 0 = $212/year
°i = (1+i)÷(1+g) - 1 = (1+0.04)÷(1+0.0582) - 1 = -0.0172 = -1.72%
NPV = -FC + ADSTOT x (P/A, g, °i , LY) = -4,000 + 212 x (P/A,5.82%,-1.72%,18) = $-1,328.61
65
3.3 Upgrading to a Programmable Thermostat
In this section the upgrade of a non-programmable thermostat to a programmable thermostat
is considered. The programmable thermostat enables the predetermined setting of temperature
changes and it is this variable temperature that saves energy. The calculation procedure used
here is based on the Energy Star’s Life Cycle Cost Estimate for an ENERGY STAR Qualified
Programmable Thermostats found on the American Energy Star’s website [PTHRM].
To determine the amount of energy saved the average amount of temperature setback must
first be calculated. The calculator asks the users to enter their normal room temperature
without setbacks, the night time temperature, the daytime temperature, the number of hours
temperature is set-back in the night and during daytime on both weekdays and weekends.
From this information, the weighted average setpoint temperature (weighted by the number of
hours of set-back) is calculated. Then the average degree setback is calculated by subtracting
the weighted average setpoint temperature from the entered normal room temperature without
setback. The average degree setback is multiplied by 3%/°C (as suggested by the Energy Star’s
procedure [PTHRM]) to get the percentage of annual heating energy saved. This is then
multiplied by the user’s current annual heating fuel consumption to calculate the amount of the
heating fuels saved.
The savings in CO2 emissions, and the net present value of the project are calculated in quite
the same manner as previously done for the case of the furnace.
66
Algorithm
# Term Input Questions Units Defaulted? 1 PROV What province do you live in? -- 2 TNORM Temperature without set-back °C 3 TNT Night-time temperature °C 4 TDT Daytime temperature °C 5 HNT_WD Weekday night-time set-back hours hours
6 HDT_WD Weekday daytime set-back hours hours
7 HNT_WE Weekend night-time set-back hours hours
8 HDT_WE Weekend daytime set-back hours hours
9 HF What fuel does your heating system use? (EL/NG/HO) --
HF=EL kWh HF=NG m3
10 ACHF_C
Current annual heating fuel consumption
HF=HO L
HF = EL kg/kWh HF = NG kg/m3
11 CO2EMHF Emission factor for HF heating fuel in PROV province
HF = HO kg/L
12 LY Life of thermostat Years HF=EL $/kWh HF=NG $/m3
13 PHF Price of heating fuel HF=HO $/L
14 FC First cost $ 15 i Interest rate % 16 g Average annual rate of growth in energy prices % 17 PCO2 Price of CO2 emission $/1000kg
Set defaults: LY to LY_DEF, PHF to PHF_DEF(HF, PROV), i to i_DEF,
PCO2 to PCO2_DEF, CO2EMHF to CO2EMHF_DEF(HF,PROV)
HNORM_WD = 24 - HNT_WD - HDT_WD
HNORM_WE = 24 - HNT_WE - HDT_WE
AST = (5÷7)x(HNT_WD x TNT + HDT_WD x TDT + HNORM_WD x TNORM)÷24
+ (2÷7)x(HNT_WE x TNT + HDT_WE x TDT + HNORM_WE x TNORM)÷24
ADS = TNORM - AST
HFS = ACHF_C x PSD x ADS
CO2SAVHF = HFS x CO2EMHF
L_CO2SAV = CO2SAVHF x LY
ADSHF = HFS x PHF
67
ADSCO2 = CO2SAVHF ÷ 1000 x PCO2
ADSTOT = ADSHF + ADSCO2
°i = (1+i)÷(1+g) - 1
NPV = -FC + ADSTOT x (P/A, g, °i , LY)
Term Definition Units Value of Constant
LY_DEF Default value for life if new thermostat Years Table 3-3 HF = EL $/kWh HF = NG $/m3 PHF_DEF
(HF,PROV) Default value for price of HF in PROV province: Lookup from table 3-1
HF = HO $/L Table 3-1
i_DEF Default value for interest rate % 4.00 PCO2_DEF Default value for price of CO2 emission $/1000kg 0
HF = EL kg/kWh table 3-2 HF = NG kg/m3 1.89
CO2EMHF_ DEF (HF,PROV)
Emission factor for HF heating fuel in PROV province
HF = HO kg/L 3.124 L_CO2SAV Total saving in CO2 emission over lifetime of new furnace kg -- HNORM_WD Daily hours at TNORM on a weekday hours -- HNORM_WE Daily hours at TNORM on a weekend day hours -- AST Average set-point temperature °C ADS Average degree setback °C
HF = EL kWh/year HF = NG m3/year HFS Heating fuel saving HF = HO L/year
--
PSD Percentage saving per degree of setback %/°C 3
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year --
L_CO2SAV Total saving in CO2 emission over lifetime of new furnace kg -- ADSHF Annual dollar saving from reduction in HF consumption $/year -- ADSCO2 Annual dollar saving from reduction in CO2 emission $/year -- ADSTOT Total annual dollar saving $/year -- NPV Net present value $ --
(P/A, i, LY) Factor to convert annuity at interest rate i, over LY years to present value -- --
Notes on Input Questions
All the input variables here are quite straightforward or are variables whose inputs have been
explained in the previous sections and so there are no new input variables of interest.
68
Sample Calculation
# Term Input Questions Units Sample Input
1 PROV What province do you live in? -- ON 2 TNORM Temperature without set-back °C 23 3 TNT Night-time temperature °C 20 4 TDT Daytime temperature °C 18 5 HNT_WD Weekday night-time set-back hours hours 8
6 HDT_WD Weekday daytime set-back hours hours 10
7 HNT_WE Weekend night-time set-back hours hours 9
8 HDT_WE Weekend daytime set-back hours hours 4
9 HF What fuel does your heating system use? (EL/NG/HO) -- NG
10
ACHF_C Current annual heating fuel consumption HF = NG m3 3,000
11 CO2EMHF Emission factor for HF heating fuel in PROV province HF = NG kg/m3 1.89
12 LY Life of thermostat Years 18 13 PHF Price of heating fuel HF = NG $/m3 0.35 14 FC First cost $ 90.00 15 I Interest rate % 4% 16 g Average annual rate of growth in energy prices % 5.82 17 PCO2 Price of CO2 emission $/1000kg 0 HNORM_WD = 24 - HNT_WD - HDT_WD = 24 – 8 – 10 = 6 hours
HNORM_WE = 24 - HNT_WE - HDT_WE = 24 – 9 – 4 = 11 hours
AST = (5÷7)x(HNT_WD x TNT + HDT_WD x TDT + HNORM_WD x TNORM)÷24
+ (2÷7)x(HNT_WE x TNT + HDT_WE x TDT + HNORM_WE x TNORM)÷24
= (5÷7)x(8x20 + 10x18 + 6x23)÷24 + (2÷7)x(9x20 + 4x18 + 11x23)÷24 = 20.24 °C
ADS = TNORM – AST = 23 – 20.24 = 2.76°C
HFS = ACHF_C x PSD x ADS = 3000m3 x 3%/°C x 2.76°C = 248.57 m3/year
CO2SAVHF = HFS x CO2EMHF = 248.57 m3/year x 1.89 kg/m3 = 469.80 kg/year
L_CO2SAV = CO2SAVHF x LY = 469.80 x 18 = 8,456.40 kg
ADSHF = HFS x PHF = 248.57m3/year x $0.35/m3 = $87.00/year
ADSCO2 = CO2SAVHF ÷ 1000 x PCO2 = 469.80 ÷ 1000 x 0 = 0
ADSTOT = ADSHF + ADSCO2 = 87.00 + 0 = $87.00/year
°i = (1+i)÷(1+g) - 1 = (1+0.04)÷(1+0.0582) - 1 = -0.0172 = -1.72%
NPV = -FC + ADSTOT x (P/A, g, °i , LY) = -90+87x(P/A,5.82%,-1.72%,18) = $1,408.82
69
3.4 Increasing Building Envelope Insulation
This section considers the task of increasing the building envelope insulation which reduces the
amount of energy lost through heat transfer. To estimate the building envelope heat lost Ivanco
et. al. use the following formula published in an IEEE Conference Paper [IVAN07]:
HDDRA
Hn
i i
i∑=
⎟⎟⎠
⎞⎜⎜⎝
⎛=
1
where: Ai = surface area i of the building envelope area, m2
Ri = thermal resistance of area i, m2.K/W
HDD = heating degree-days, K.day
This formula appears quite logically sound as it follows the general format of the heat transfer
equation [BASM07]
q = RAΔT
where R is the thermal resistance , A is the cross-sectional area , and ΔT is the temperature
difference between the high and low temperature regions between which the heat transfer is
taking place. In the Ivanco equation the HDD is used for ΔT because it represents the annual
cumulative temperature differences between the daily average outdoor temperatures and 18°C
for all days when the average temperature is bellow 18°C. Even though HDD is the sum of
temperature differences as opposed to just one temperature difference it seems logical that this
sum would work just as well in the heat transfer equation because the RA factors multiplying
the temperature differences are all the same daily. This is demonstrated mathematically by:
RAΔT1 +
RAΔT2 +
RAΔT3 +
RAΔT4 + … =
RA (ΔT1 + ΔT2 + ΔT3 + ΔT4 + …) = ∑Δ
iiT
RA
70
Increasing the insulation only increases the value of Ri without affecting the values of Ai or HDD
and so the incremental saving in heat loss from increasing insulation of area Ai of the building
envelope can be calculated by:
HDDRRR
AHDDRR
AHDD
RA
HACC
iAC
i
C
i⎟⎟⎠
⎞⎜⎜⎝
⎛+
−=+
−=Δ11
where ΔH is the energy saving, RC is the current thermal resistance, and RA is the thermal
resistance added. In the algorithm that follows, R is expressed as RSI to signify that the units
of the thermal resistance are standard international (SI) units, i.e. m2.K/W.
Having calculated the energy saving, the savings in CO2 emissions, and the net present value of
the project are calculated in quite the same manner as previously done for the case of the
furnace.
Algorithm
# Term Input Questions Units Defaulted? 1 PROV What province do you live in? -- 2 HDD Heating degree days K.days 3 A Area of insulation m2 4 RSIC Current insulation RSI amount m2.K/W 5 RSIA Additional insulation RSI amount m2.K/W
6 HF What fuel does your heating system use? (EL/NG/HO) --
7 EFF Efficiency of heating system % HF = EL kg/kWh HF = NG kg/m3 8 CO2EMHF
Emission factor for HF heating fuel in PROV province
HF = HO kg/L
9 LY Life of new insulation Years HF=EL $/kWh HF=NG $/m3 10 PHF Price of heating fuel HF=HO $/L
11 FC First cost $ 12 i Interest rate % 13 g Average annual rate of growth in energy prices % 14 PCO2 Price of CO2 emission $/1000kg
Set defaults: LY to LY_DEF, PHF to PHF_DEF(HF, PROV), i to i_DEF, PCO2 to PCO2_DEF,
71
CO2EMHF to CO2EMHF_DEF(HF,PROV)
AELC = A ÷ RSIC x HDD x 24 ÷ 1000
AELN = A ÷ (RSIC + RSIA) x HDD x 24 ÷ 1000
ΔAEL = AELC – AELN
HES = ΔAEL x CONVFkBTU/kWh
HFS = HES ÷ HEHF(HF) ÷ EFF
CO2SAVHF = HFS x CO2EMHF
L_CO2SAV = CO2SAVHF x LY
ADSHF = HFS x PHF
ADSCO2 = CO2SAVHF ÷ 1000 x PCO2
ADSTOT = ADSHF + ADSCO2
°i = (1+i)÷(1+g) - 1
NPV = -FC + ADSTOT x (P/A, g, °i , LY)
Term Definition Units Value of Constant
LY_DEF Default value for life of new insulation Years Table 3-3 HF = EL $/kWh HF = NG $/m3 PHF_DEF
(HF,PROV) Default value for price of HF in PROV province: Lookup from table 3-1
HF = HO $/L Table 3-1
i_DEF Default value for interest rate % 4.00 PCO2_DEF Default value for price of CO2 emission $/1000kg 0
HF = EL kg/kWh table 3-2 HF = NG Kg/m3 1.89 CO2EMHF_DEF
(HF,PROV) Default value for emission factor for HF heating fuel in PROV province
HF = HO Kg/L 3.124
AELC Current annual energy loss through subject section of ceiling insulation kWh/year --
AELN New annual energy loss through subject section of ceiling insulation kWh/year --
ΔAEL Reduction in annual energy loss kWh/year -- HES Heat energy saving kBTU --
HF = EL kWh/year HF = NG m3/year HFS Heating fuel saving HF = HO L/year
--
CONVFkBTU/kWh Conversion factor: kWh to kBTU kBTU/kWh 3.4 HF = EL kBTU/kWh 3.4 HF = NG kBTU/m3 35.5 HEHF(HF) Heat energy of HF heating fuel HF = HO kBTU/L 39.6
72
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year --
L_CO2SAV Total saving in CO2 emission over lifetime of new insulation kg --
ADSHF Annual dollar saving from reduction in HF consumption $/year -- ADSCO2 Annual dollar saving from reduction in CO2 emission $/year -- ADSTOT Total annual dollar saving $/year -- NPV Net present value $ --
(P/A, i, LY) Factor to convert annuity at interest rate i, over LY years to present value -- --
Notes on Input Questions
HDD Users can obtain the normal average HDD for their city or the city they live closest to
from Environment Canada at:
http://climate.weatheroffice.ec.gc.ca/climate_normals/index_e.html
RSIA The RSI value of insulation is printed on the insulation packaging by the manufacturer.
EFF The efficiency of an oil or gas furnace will be the annual fuel usage efficiency (AFUE)
which is already expressed in % units. The efficiency of a heat pump is expressed as
either the heating coefficient of performance (COP) or the heating seasonal performance
factor (HSPF). The COP is a dimensionless ratio so will have to be multiplied by 100 to
convert it to % units. The HSPF has units of kBTU/kWh so will have to be divided by
CONVFkBTU/kWh to convert to a dimensionless ratio and then multiplied by 100 to change
to % units. The source of the user’s current heating system’s AFUE, COP, or HSPF is
already discussed earlier under the furnace and heat pump upgrade sections.
73
Sample Calculation
# Term Input Questions Units Sample Input
1 PROV What province do you live in? -- ON 2 HDD Heating degree days K.days 3570 3 A Area of insulation m2 1.0 4 RSIC Current insulation RSI amount m2.K/W 2 5 RSIA Additional insulation RSI amount m2.K/W 7
6 HF What fuel does your heating system use? (EL/NG/HO) -- NG
7 EFF Efficiency of heating system % 0.90
8 CO2EMHF Emission factor for HF heating fuel in PROV province HF = NG kg/m3 1.89
9 LY Life of new insulation Years 30 10 PHF Price of heating fuel HF=NG $/m3 0.35 11 FC First cost $ 17 12 I Interest rate % 4.00 13 g Average annual rate of growth in energy prices % 5.82 14 PCO2 Price of CO2 emission $/1000kg 0
AELC = A ÷ RSIC x HDD x 24 ÷ 1000 = 1 ÷ 2 x 3570 x 24 ÷ 1000 = 42.84
AELN = A ÷ (RSIC + RSIA) x HDD x 24 ÷ 1000 = 1 ÷ (2 +7) x 3570 x 24 ÷ 1000 = 9.52
ΔAEL = AELC – AELN = 42.84 - 9.52 = 33.3 kWh/year
HES = ΔAEL x CONVFkBTU/kWh = 33.3 x 3.4 = 113.29 kBTU/year
HFS = HES ÷ HEHF(HF) ÷ EFF = 113.29 ÷ 35.5 ÷ 0.9 = 3.55 m3/year
CO2SAVHF = HFS x CO2EMHF = 3.55 x 1.89 = 6.70 kg/year
L_CO2SAV = CO2SAVHF x LY = 6.70 x 30 = 201 kg
ADSHF = HFS x PHF = 3.55 x 0.35 = $1.24/year
ADSCO2 = CO2SAVHF ÷ 1000 x PCO2 = 6.70 ÷ 1000 x 0 = 0
ADSTOT = ADSHF + ADSCO2 = $1.24 + 0 = $1.24/year
°i = (1+i)÷(1+g) - 1 = (1+0.04)÷(1+0.0582) - 1 = -0.0172 = -1.72%
NPV = -FC + ADSTOT x (P/A, g, °i , LY) = -17+1.24 x(P/A,5.82%,-1.72%,30) = $29.56
74
3.5 Upgrading Window Efficiency
The scenario of upgrading a window is dealt with in this section. The Canadian Standards
Association CSA 440.2-04 gives a clear procedure for calculating the rate of net heat loss or
gain through a window using the window’s energy-related characteristics such as SHGC and U-
value, the geographical location and the orientation of the window as inputs [CSA04]. In CSA
440.2-04 the rate of net heat transfer through the windows during the heating season is
termed the specific energy rating (ERS) and is calculated as follows:
ERS = FS x SHGCW x R – [(Ti - To) x UW] – [KPF x (L75/AW)]
where
ERS = specific energy rating, W/m2
FS = average rate of usable incident solar radiation on window, W/m2
SHGCW = window solar heat gain coefficient, dimensionless
R = solar gain reduction factor (set to 0.8), dimensionless
Ti = average indoor temperature, °C
To = average outdoor temperature, °C
UW = window overall coefficient of heat transfer, W/(m2.K)
KPF = factor that includes a conversion factor and the local pressure factor, W.h/m3
L75 = window air leakage rate at pressure differential of 75 Pa, m3/h
AW = total window area, m2
CSA 440.2-04 explains that the ERS consists of three terms: FS x SHGCW x R representing the
average rate of energy gain from solar radiation, (Ti - To) x UW representing average heat loss
rate by transmission and, KPF x (L75/AW) representing the average heat loss rate by infiltration.
CSA 440.2-04 also explains how the variables in the ERS equation can be calculated. Variables
like SHGCW, and UW are determined by the standardized tests developed by the CSA and these
75
variables are provided by the window manufacturer. L75 is also determined by standardized
testing but it was found that window manufacturers do not generally list L75 in the
specifications. However, heat loss by infiltration only accounts for about 10% of the windows
energy loss [CSA04] thus even if L75 is entered as zero it would not change the accuracy of the
ERS value too much.
Determination of Ti - To and KPF is done by looking up their values from a table provided in the
CSA 440.2-04 that lists the average temperature difference Ti - To and the average KPF for
major Canadian cities. CSA 440.2-04 suggests that for cities that are not listed in the table, a
major city that is closest to the unlisted city be picked. A sample of this table is shown in table
3-5.
To determine FS, the solar heat gain index (SGI) is calculated as follows:
SGI = SHGCW x fl
W
AA
where Afl is the total above-grade floor area of the house (m2) and SHGCW, and AW are as
defined earlier. FS can then be looked up from table 3-5 using SGI, city of the dwelling, and the
orientation of the window. For values of SGI that are not listed in the table CSA 440.2-04
suggests that FS be determined by interpolation.
The value of R in the ERS is set to 0.8 as suggested by CSA 440.2-04. Finally with all the
source of values of all variables in the ERS equation accounted for, the ERS itself can be
calculated.
Having calculated the energy saving, the savings in CO2 emissions, and the net present value of
the project are calculated in the same manner as done previously.
76
Table 3-5 Lookup table for FS, KPF, Ti – To using SGI, orientation, and city as input
Source: CSA 440.2-04 standard [CSA04]
Algorithm
# Term Input Questions Units Defaulted? 1 PROV What province do you live in? -- 2 CITY Select what major city is closest to you -- 3 ORNT Select the orientation of your window
(N, NE, E, SE, S, SW, W, NW) --
4 SHGCC What is the Solar Heat Gain Coefficient (SHGC) of your current window? --
5 UC What is the U of your current window? W/m2.K 6 AWTOT What is the total area of ALL windows in your
house? m2
7 AFL What is the floor area of your house? m2 8 L75_C What is your current window’s air leakage rate at
a pressure differential of 75 Pa m3/h
9 SHGCN What is the Solar Heat Gain Coefficient (SHGC) of your NEW window? --
10 UN What is the U of your new window? W/m2.K 11 L75_N What is your new window’s air leakage rate at a
pressure differential of 75 Pa m3/h
12 AW Area of window m2 13 NHM How many months do you heat? months 14 HF What fuel does your heating system use?
(EL/NG/HO) --
77
15 EFF Efficiency of heating system % HF = EL kg/kWh HF = NG kg/m3
16
CO2EMHF Emission factor for HF heating fuel in PROV province HF = HO kg/L
17 LY Life of window Years HF=EL $/kWh HF=NG $/m3
18 PHF Price of heating fuel
HF=HO $/L
19 FC First cost $ 20 i Interest rate % 21 g Average annual rate of growth in energy prices % 22 PCO2 Price of CO2 emission $/1000kg
Set defaults: L75_C to L75_DEF, L75_N to L75_DEF, LY to LY_DEF, PHF to PHF_DEF(HF, PROV),
i to i_DEF, PCO2 to PCO2_DEF, CO2EMHF to CO2EMHF_DEF(HF,PROV)
Lookup FS_H, FS_L, KPF, and (Ti – To) from table 5-3 using CITY, and ORNT
SGIC = SHGCC x AWTOT ÷ AFL
Interpolate to get FS_C using FS_H, FS_L, and SGIC: FS_C = FS_L + ( )174.0174.0044.0__ −⎟⎟
⎠
⎞⎜⎜⎝
⎛
−
−C
LSHS SGIFF
ERSC = FS_C x SHGCC x 0.8 - (Ti – To)x UC - KPF x L75_C ÷ AWTOT
SGIN = SHGCN x AWTOT ÷ AFL
Interpolate to get FS_N using FS_H, FS_L, and SGIN: FS_N = FS_L + ( )174.0174.0044.0__ −⎟⎟
⎠
⎞⎜⎜⎝
⎛
−
−N
LSHS SGIFF
ERSN = FS_N x SHGCN x 0.8 - (Ti – To)x UN - KPF x L75_N ÷ AWTOT
ΔERS = ERSN – ERSC
HES = ΔERS x AW x 24 x 365 x (NHM /12) x CONVFkBTU/kWh ÷ 1000
HFS = HES ÷ HEHF(HF) ÷ EFF
CO2SAVHF = HFS x CO2EMHF
L_CO2SAV = CO2SAVHF x LY
ADSHF = HFS x PHF
ADSCO2 = CO2SAVHF ÷ 1000 x PCO2
ADSTOT = ADSHF + ADSCO2
78
°i = (1+i)÷(1+g) - 1
NPV = -FC + ADSTOT x (P/A, g, °i , LY)
Term Definition Units Value of Constant
L75_DEF Default value for window’s air leakage rate at a pressure differential of 75 Pa m3/h 0
LY_DEF Default value for life of new windows Years Table 3-3 HF = EL $/kWh HF = NG $/m3 PHF_DEF
(HF,PROV) Default value for price of HF in PROV province: Lookup from table 3-1
HF = HO $/L table 3-1
i_DEF Default value for interest rate % 4.00 PCO2_DEF Default value for price of CO2 emission $/1000kg 0
HF = EL kg/kWh table 3-2 HF = NG kg/m3 1.89 CO2EMHF_DEF
(HF,PROV) Emission factor for HF heating fuel in PROV province
HF = HO kg/L 3.124 FS_H Factor used in ERS calculation: high value from table W/m2 --
FS_L Factor used in ERS calculation: low value from table W/m2 --
KPF Factor used in ERS calculation W.h/m3 -- (Ti – To) Factor used in ERS calculation °C -- SGIC Current window: factor used in FS calculation -- -- FS_C Current window: average rate of usable incident solar
radiation during heating season W/m2 --
ERSC Current window: specific energy rating W/m2 -- SGIN New window: factor used in FS calculation -- -- FS_N New Window: average rate of usable incident solar
radiation during heating season W/m2 --
ERSN New window: specific energy rating W/m2 -- ΔERS Gain in specific energy rating W/m2 -- HES Heat energy saving kBTU --
HF = EL kWh/year HF = NG m3/year HFS Heating fuel saving HF = HO L/year
--
CONVFkBTU/kWh Conversion factor: kWh to kBTU kBTU/kWh 3.4 HF = EL kBTU/kWh 3.4 HF = NG kBTU/m3 35.5 HEHF(HF) Heat energy of HF heating fuel HF = HO kBTU/L 39.6
L_CO2SAV Total saving in CO2 emission over lifetime of new furnace kg --
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year --
L_CO2SAV Total saving in CO2 emission over lifetime of new furnace kg --
ADSHF Annual dollar saving from reduction in HF consumption $/year -- ADSCO2 Annual dollar saving from reduction in CO2 emission $/year -- ADSTOT Total annual dollar saving $/year -- NPV Net present value $ -- (P/A, i, LY) Factor to convert annuity at interest rate i, over LY -- --
79
years to present value
Notes on Input Questions
ORNT This is the orientation of the window currently being considered for upgrade.
AWTOT The total area of ALL windows in the house can be determined by measuring the
dimensions (length and width) of all windows or by measuring the dimensions of a
sample group of windows, calculating the average windows area and multiplying it by
the total number of windows in the house.
AFL The floor area of the house is known by the dwelling’s owner as it is one of the key
parameters that influences the price of the house and is thus discussed during the
purchase of a house.
SHGCN Posted by manufacturer on new window
UN Posted by manufacturer on new window
L75_N Posted by manufacturer on new window
AW The area of the window being considered for upgrade can be determined by measuring
the length and width of the window and multiplying the dimensions.
NHM This is the user’s best estimate of the average number of months heating is turned on
in the dwelling annually.
Sample Calculation
# Term Input Questions Units Sample Input
1 PROV What province do you live in? -- QB 2 CITY Select what major city is closest to you -- Montreal 3 ORNT Select the orientation of your window
(N, NE, E, SE, S, SW, W, NW) -- N
4 SHGCC What is the Solar Heat Gain Coefficient (SHGC) of your current window? -- 0.16
5 UC What is the U of your current window? W/m2.K 1.99 6 AWTOT What is the total area of ALL windows in your
house? m2 10
7 AFL What is the floor area of your house? m2 100
80
8 L75_C What is your current window’s air leakage rate at a pressure differential of 75 Pa m3/h 0
9 SHGCN What is the Solar Heat Gain Coefficient (SHGC) of your NEW window? -- 0.43
10 UN What is the U of your new window? W/m2.K 1.31 11 L75_N What is your new window’s air leakage rate at a
pressure differential of 75 Pa m3/h 0
12 AW Area of window m2 4.46 13 NHM How many months do you heat? months 8 14 HF What fuel does your heating system use?
(EL/NG/HO) -- NG
15 EFF Efficiency of heating system % 90% 16
CO2EMHF Emission factor for HF heating fuel in PROV province HF = NG kg/m3 1.89
17 LY Life of window Years 10 18 PHF Price of heating fuel HF=NG $/m3 0.43 19 FC First cost $ 1854 21 i Interest rate % 4.00 22 g Average annual rate of growth in energy prices % 5.82 23 PCO2 Price of CO2 emission $/1000kg 0
Lookup FS_H, FS_L, KPF, and (Ti – To) from table 5-3 using CITY, and ORNT:
FS_H = 35.4
FS_L = 33.8
KPF = 0.407
(Ti – To) = 22.7
SGIC = SHGCC x AWTOT ÷ AFL = 0.16 x 10 ÷ 100 = 0.016
Interpolate to get FS_C using FS_H, FS_L, and SGIC:
FS_C = FS_L + ( )174.0174.0044.0__ −⎟⎟
⎠
⎞⎜⎜⎝
⎛
−
−C
LSHS SGIFF
= 33.8 + ( )174.0016.0174.0044.08.33 35.4
−⎟⎠
⎞⎜⎝
⎛−− = 35.7
ERSC = FS_C x SHGCC x 0.8 - (Ti – To)x UC - KPF x L75_C ÷ AWTOT
= 35.7 x 0.16 x 0.8 – 22.7 x 1.99 – 0.407 x 0 ÷ 10 = -40.6 W/m2
SGIN = SHGCN x AWTOT ÷ AFL = 0.43 x 10 ÷ 100 = 0.043
Interpolate to get FS_N using FS_H, FS_L, and SGIN:
FS_N = FS_L + ( )174.0174.0044.0__ −⎟⎟
⎠
⎞⎜⎜⎝
⎛
−
−N
LSHS SGIFF
= 33.8 + ( )174.0043.0174.0044.08.33 35.4
−⎟⎠
⎞⎜⎝
⎛−− = 35.4
ERSN = FS_N x SHGCN x 0.8 - (Ti – To)x UN - KPF x L75_N ÷ AWTOT
81
= 35.4 x 0.43 x 0.8 – 22.7 x 1.31 – 0.407 x 0 ÷ 10 = -17.5 W/m2
ΔERS = ERSN – ERSC = -17.5 – (-40.6) = 23.1 W/m2
HES = ΔERS x AW x 24 x 365 x (NHM /12) x CONVFkBTU/kWh ÷ 1000
= 23.1 x 4.46 x 24 x 365 x (8/12) x 3.4 ÷ 1000 = 2043.8 kBTU/year
HFS = HES ÷ HEHF(HF) ÷ EFF = 2043.8 ÷ 35.5 ÷ 0.90 = 63.97 m3/year
CO2SAVHF = HFS x CO2EMHF = 63.97 x 1.89 = 120.90 kg/year
L_CO2SAV = CO2SAVHF x LY = 120.90 x 10 = 1209 kg
ADSHF = HFS x PHF = 63.97 x 0.43 = $27.51/year
ADSCO2 = CO2SAVHF ÷ 1000 x PCO2 = 120.9 ÷ 1000 x 0 = 0
ADSTOT = ADSHF + ADSCO2 = $27.51+ 0 = $27.51/year
°i = (1+i)÷(1+g) - 1 = (1+0.04)÷(1+0.0582) - 1 = -0.0172 = -1.72%
NPV = -FC + ADSTOT x (P/A, g, °i , LY) = -1854+ 27.51x(P/A,5.82%,-1.72%,10) = $-1567.65
82
3.6 Upgrading Lighting Efficiency
The saving in electricity from upgrading an incandescent light bulb (ILB) to a compact
fluorescent light bulb (CFLB) is straightforward to calculate but total energy saved from this
upgrade is somewhat more complex. That is because the more efficient CFLB which uses less
electricity to produce the same amount of light as the inefficient ILB also produces considerably
less heat (the CFLB’s higher efficiency comes from its ability to convert much more of the
electricity consumed into light rather than heat). However, during the cold winter months of
Canada this reduction in heat production has to be compensated by increased load on the
dwelling’s space heating system leading to a trade-off of electricity saved against the increase
in heating fuel consumption. Conversely, during the warmer months, the reduction in heat
production by lighting is doubly beneficial because the load on the dwelling’s cooling system is
reduced leading to further energy savings. The overall annual energy (and CO2 emission)
saving is highly dependent on each dwelling’s unique characteristics and can be calculated as
follows.
The saving in annual electricity consumed by the bulb is calculated by determining the change
in power rating of the bulb and multiplying it by the average daily usage (in hours) and by the
number of days in a year. The portion of this saving in electricity consumption that happens in
the heating months has to be compensated by the heating system. This portion is calculated by
dividing the annual saving by 12 to get the monthly average and then multiplying it by the
average number of heating months supplied by the user. The increase in heating energy
required is then equal to this calculated portion. To mimic the terminology used for the other
cases so far, the algorithm calculates the saving in heating energy instead of the increase, and
this is just the negative of the calculated increase. The saving in heating fuel is calculated by
dividing the saving in heating energy by the unit heat content of the heating fuel (electricity,
natural gas or heating oil) and then by the efficiency of the heating system (furnace or a heat
83
pump). On the other hand, the saving in fuel used for cooling is calculated in a similar manner
using the portion of electricity consumption saving that takes place during the cooling months,
and the efficiency of the cooling system.
To calculate the saving in CO2 emission and the annual dollar saving as result of the total
annual energy saving it is necessary to know the fuel of each form of energy being saved (i.e.
the saving in electricity consumption at the bulb, heating energy, and cooling energy of the
dwelling). The knowledge of what fuel is used is important because the unit CO2 emission factor
and the unit price of each fuel (electricity, natural gas, or heating oil) is different. The fuel for
electricity consumption at the bulb is quite simply electricity. The fuel for the heating energy of
the dwelling can be electricity (if a heat pump or a radiant heater is used), natural gas or
heating oil (for a furnace). The fuel for cooling energy is almost always electricity since a heat
pump or an air conditioner (which is also just a heat pump) is used for cooling. Since the fuel
for both the saving in electricity consumption and cooling is electricity these savings can be
treated together by adding them up. This gives rise to the separate treatment of savings from
electricity and the savings from the heating fuel as shown in the algorithm. Once the CO2
emission savings for electricity and the heating fuel are separately calculated they can be
summed up to determine the total CO2 emission saving. The same is done for the total annual
dollar savings. The lifetime savings in CO2 emissions, and the net present value of the project
are calculated in the same manner as done previously.
Algorithm
# Term Input Questions Units Defaulted? 1 PROV What province do you live in? -- 2 PWCF Power rating of CFLB W 3 PWIL Equivalent power rating of ILB W 4 ADU Average daily usage hours 5 NHM Number of months of heating months 6 NCM Number of months of cooling months 7 HF Fuel source for heating system (EL/NG/HO) 8 EFFH Efficiency of heating system --
84
9 EFFC Efficiency of cooling system -- HF = EL kg/kWh HF = NG kg/m3
10
CO2EMHF Emission factor for HF heating fuel in PROV province HF = HO kg/L
11 CO2EMEL Emission factor for electricity in PROV province kg/kWh 12 LH Life of CFLB hours
HF=EL $/kWh HF=NG $/m3
13 PHF Price of heating fuel
HF=HO $/L
14 PEL Price of electricity $/kWh 15 FC First cost $ 16 i Interest rate % 17 g Average annual rate of growth in energy prices % 18 PCO2 Price of CO2 emission $/1000kg
Set defaults: LH to LH_DEF, PHF to PHF_DEF(HF, PROV), PEL to PHF_DEF(HF=EL, PROV),
i to i_DEF, PCO2 to PCO2_DEF, CO2EMHF to CO2EMHF_DEF(HF,PROV),
CO2EMEL to CO2EMHF_DEF(HF=EL, PROV)
AECCF = PWCF x ADU x 365 ÷ 1000
AECIL = PWIL x ADU x 365 ÷ 1000
ΔAEC = AECIL - AECCF
HES = -ΔAEC x (NHM /12) x CONVFkBTU/kWh
HFS = HES ÷ HEHF(HF) ÷ EFFH
CES = ΔAEC x (NCM /12) x CONVFkBTU/kWh
CFS = CES ÷ CONVFkBTU/kWh ÷ EFFC
CO2SAVEL = (ΔAEC + CFS) x CO2EMEL
CO2SAVHF = HFS x CO2EMHF
CO2SAVTOT = CO2SAVEL + CO2SAVHF
LY = LH ÷ (ADU x 365)
L_CO2SAV = CO2SAVTOT x LY
ADSEL = (ΔAEC + CFS) x PEL
ADSHF = HFS x PHF
ADSCO2 = CO2SAVTOT ÷ 1000 x PCO2
85
ADSTOT = ADSEL + ADSHF + ADSCO2
°i = (1+i)÷(1+g) - 1
NPV = -FC + ADSTOT x (P/A, g, °i , LY)
Term Definition Units Value of Constant
LH_DEF Default value for life of new CFLB hours 10,000 HF = EL $/kWh HF = NG $/m3 PHF_DEF
(HF,PROV) Default value for price of HF in PROV province: Lookup from table 3-1 HF = HO $/L
table 3-1
i_DEF Default value for interest rate % 4.00 PCO2_DEF Default value for price of CO2 $/1000kg 0
HF = EL kg/kWh table 3-2 HF = NG kg/m3 1.89 CO2EMHF_DEF
(HF,PROV) Default value of emission factor for HF heating fuel in PROV province HF = HO kg/L 3.124
AECCF Annual energy consumption of new CFLB kWh/year -- AECIL Annual energy consumption of current ILB kWh/year -- ΔAEC Change in annual energy consumption from switching kWh/year -- HES Heat energy saving kBTU/year --
HF = EL kWh/year HF = NG m3/year
HFS Heating fuel saving HF = HO L/year --
CONVFkBTU/kWh Conversion factor: kWh to kBTU kBTU/kWh 3.4
HF = EL kBTU/kWh 1.0 HF = NG kBTU/m3 35.5
HEHF(HF) Heat energy of HF heating fuel HF = HO kBTU/L 39.6 CES Cooling energy saving kBTU/year -- CFS Cooling fuel saving kWh/year --
CO2SAVEL Saving in CO2 emission from reduction in electricity consumption kg/year --
CO2SAVHF
Saving in CO2 emission from reduction in HF consumption kg/year --
CO2SAVTOT Total annual saving in CO2 emission kg/year LY Life of new CFLB in years Years --
L_CO2SAV Total saving in CO2 emission over lifetime of new furnace Kg --
ADSEL Annual dollar saving from reduction in EL consumption $/year -- ADSHF Annual dollar saving from reduction in HF consumption $/year -- ADSCO2 Annual dollar saving from reduction in CO2 emission $/year -- ADSTOT Total annual dollar saving $/year -- NPV Net present value $ -- (P/A, i, LY) Factor to convert annuity at interest rate i, over LY
years to present value -- --
Notes on Input Questions
86
PWCF Printed by manufacturer on CFLB
PWIL Printed by manufacturer on ILB
ADU Each bulb has a different daily utilization rate depending factors such as its location in
the dwelling, the number of windows, and the habits of the residents. This input allows
the user to give a best estimate of the average daily usage of the particular bulb being
considered. If the bulb has a periodic pattern of usage over a time span (such as less
usage on weekdays but more on the weekend) the user can take the total usage hours
over the time span and divide it by the number of days in the time span to get the
average daily usage.
Sample Calculation
# Term Input Questions Units Sample Input
1 PROV What province do you live in? -- AL 2 PWCF Power rating of CFLB W 9 3 PWIL Equivalent power rating of ILB W 40 4 ADU Average daily usage hours 5 5 NHM Number of months of heating months 6 6 NCM Number of months of cooling months 3 7 HF Fuel source for heating system (EL/NG/HO) NG 8 EFFH Efficiency of heating system -- 0.90 9 EFFC Efficiency of cooling system -- 2.94 10
CO2EMHF Emission factor for HF heating fuel in PROV province HF = NG kg/m3 1.89
11 CO2EMEL Emission factor for electricity in PROV province kg/kWh 0.93 12 LH Life of CFLB hours 10,000 13 PHF Price of heating fuel HF=NG $/m3 0.22 14 PEL Price of electricity $/kWh 0.10 15 FC First cost $ 3.99 16 i Interest rate % 4.00 17 g Average annual rate of growth in energy prices % 5.82 18 PCO2 Price of CO2 emission $/1000kg 0
AECCF = PWCF x ADU x 365 ÷ 1000 = 9 x 5 x 365 ÷ 1000 = 16.425 kWh/year
AECIL = PWIL x ADU x 365 ÷ 1000 = 40 x 5 x 365 ÷ 1000 = 73 kWh/year
ΔAEC = AECIL - AECCF = 73 - 16.425 = 56.6 kWh/year
HES = -ΔAEC x (NHM /12) x CONVFkBTU/kWh = -56.6 x 6/12 x 3.4 = -96.22 kBTU/year*
87
* Energy saving of 96 kBTU/year may seem like a large amount for simply changing a light bulb
but table 3-2 shows us that typical heat pumps move 16 – 60 kBTU/hour, so 96 kBTU in a year
is quite reasonable.
HFS = HES ÷ HEHF(HF) ÷ EFFH = -96.22 ÷ 35.5 ÷ 0.9 = -3.01 m3/year
CES = ΔAEC x (NCM /12) x CONVFkBTU/kWh = 56.5 x 3/12 x 3.4 = 48.025 kBTU/year
CFS = CES ÷ CONVFkBTU/kWh ÷ EFFC = 48.025 ÷ 3.4 ÷ 2.94 = 4.8 kWh/year
CO2SAVEL = (ΔAEC + CFS) x CO2EMEL = (56.6 + 4.8) x 0.93 = 57.11 kg/year
CO2SAVHF = HFS x CO2EMHF = -3.01 x 1.89 = -5.69 kg/year
CO2SAVTOT = CO2SAVEL + CO2SAVHF = 57.11 – 5.69 = 51.42 kg/year
LY = LH ÷ (ADU x 365) = 10,000 ÷ (5 x 365) = 5.48 years
L_CO2SAV = CO2SAVTOT x LY = 51.42 x 5.48 = 280.98 kg
ADSEL = (ΔAEC + CFS) x PEL = (56.6 + 4.8) x 0.10 = $6.14/year
ADSHF = HFS x PHF = -3.01 x 0.22 = $-0.66/year
ADSCO2 = CO2SAVTOT ÷ 1000 x PCO2 = 51.42 ÷ 1000 x 0 = 0
ADSTOT = ADSEL + ADSHF + ADSCO2 = 6.14 - 0.66 + 0 = $5.48/year
°i = (1+i)÷(1+g) - 1 = (1+0.04)÷(1+0.0582) - 1 = -0.0172 = -1.72%
NPV = -FC + ADSTOT x (P/A, g, °i , LY) = -3.99+5.48 x(P/A,5.82%,-1.72%, 5.48) = $26.02
88
3.7 Upgrading Refrigerator Efficiency
As in the case of upgrading lighting efficiency, upgrading refrigeration efficiency also causes an
increased demand on the dwelling’s space heating system to compensate for the reduction in
heat produced by the refrigerator in the heating months, and a reduced demand on the space
cooling system in the cooling months. The effects of this trade-off are calculated in quite the
same manner as done previously for lighting. However, calculating the initial electricity savings
associated with upgrading a refrigerator can be more involved than calculating the same for
lighting.
The annual savings in electricity consumption from upgrading the refrigerator is quite simply
the difference in annual energy consumption listed on the EnerGuide Label of the current and
new refrigerator. However, if this information is not available (quite likely the case for the
current equipment that may be so old that the EnerGuide Label is either lost or was not
required at the time of manufacturing) a series of questions may be asked to estimate the
annual energy consumption.
To estimate the annual energy consumption of the current refrigerator the documentation of
calculation methodology for the Home Energy Saver [HES07] provides a formula:
AEC = (365 x AV) ÷ EF
where AEC = Annual energy consumption (kWh/year)
AV = Adjusted volume (cubic feet)
EF = Energy factor (kWh/ cubic feet.year)
The energy factor EF is a factor that gives the efficiency of the refrigerator and can looked up
from table 3-6, also provided in [HES07]. The adjusted volume AV is a conversion of the
89
‘nominal’ volume of the refrigerator to account for the higher energy intensity of the freezer
section over the refrigerator. This adjustment is given as such:
AV = Nominal volume x (0.66 + (1 - 0.66) x 1.63)
Table 3-6 Shipment weighted energy factors (EF) for refrigerators
Source: Home Energy Saver documentation [HES07]
For estimating the annual energy consumption of a new refrigerator Canada’s Energy Efficiency
Regulations provides some help [EER]. Under the current regulations, all refrigerators sold in
90
Canada must meet specified maximum annual energy consumption limits. These limits are a
function of the adjusted volume and the product category of the refrigerator. Table 3-7 shows
the list of categories and the maximum energy consumption limit formula for each category.
Thus for a new refrigerator sold in Canada the maximum amount of energy it could consume
can be determined. Furthermore, for a refrigerator to be Energy Star certified it has to consume
at least 15% lower than the regulated limit (i.e. 85% of the limit amount or less) and so the
energy consumption for a new refrigerator that is also Energy Star certified can be estimated
even more finely.
Table 3-7 Maximum annual energy consumption limits for refrigerators
Product Type Energy
Consumption Limits (kWh/yr)
(1) Refrigerators and refrigerator-freezers with manual defrost 8.82 AV + 248.4
(2) Refrigerator freezers with partial automatic defrost 8.82 AV + 248.4
(3) Refrigerator freezers with automatic defrost with top-mounted freezer without through-the-door ice service, and all refrigerators with automatic defrost 9.80 AV + 276
(4) Refrigerator-freezers with automatic defrost with side-mounted freezer without through-the-door ice service 4.91 AV + 507.5
(5) Refrigerator-freezers with automatic defrost with bottom-mounted freezer without through-the-door ice service 4.60 AV + 459.0
(6) Refrigerator-freezers with automatic defrost with top-mounted freezer with through-the-door ice service 10.20 AV + 356.0
(7) Refrigerator-freezers with automatic defrost with side-mounted freezer with through-the-door ice service 10.10 AV + 406.0
(8) Upright freezers with manual defrost 7.55 AV + 258.3
(9) Upright freezers with automatic defrost 12.43 AV + 326.1
(10) Chest freezers and all other freezers 9.88 AV + 143.7
(11) Compact Refrigerators and Refrigerator-freezers with manual defrost 10.70 AV + 299.0
(12) Compact Refrigerator freezers with partial automatic defrost 7.00 AV + 398.0
(13) Compact Refrigerator freezers with automatic defrost with top-mounted freezer and compact all-refrigerators with automatic defrost 12.70 AV + 355.0
(14) Compact Refrigerator-freezers with automatic defrost with side-mounted freezer 7.60 AV + 501.0
(15) Compact Refrigerator-freezers with automatic defrost with bottom-mounted freezer 13.10 AV + 367.0
(16) Compact Upright freezers with manual defrost 9.78 AV + 250.8
(17) Compact Upright freezers with automatic defrost 11.40 AV + 391.0
(18) Compact Chest freezers and all other freezers 10.45 AV + 152.0
* AV = Adjusted volume, in cubic feet Source: Natural Resources Canada Energy Efficiency Regulations [EER]
91
Next, having calculated the annual savings in electricity consumption, the rest of the algorithm
proceeds exactly as described for the lighting case. The savings in heating and cooling energy
and subsequently heating and cooling fuel are calculated. Then the savings in CO2 emissions is
aggregated from the multiple sources involved and then the dollar savings are calculated.
Algorithm
# Term Input Questions Units Defaulted? 1 PROV What province do you live in? --
2A-1 AECC Current refrigerator: annual energy consumption from EnerGuide Label kWh/year
2B-1 YEARC Current refrigerator: year of purchase -- 2B-2 VC Current refrigerator: volume of refrigerator ft3 2B-3 DFRSTC Current refrigerator: manual, auto defrost, or
don’t know --
2B-4 FZRC Current refrigerator: freezer is at top or side-by-side --
3A-1 AECN New refrigerator: annual energy consumption from EnerGuide Label kWh/year
3B-1 VN New refrigerator: volume of refrigerator (cu. Ft.) ft3 3B-2 CATN New refrigerator: category type (1 – 18) -- 3B-3 ESTARN New refrigerator: energy star or not? --
4 NHM Number of months of heating months 5 NCM Number of months of cooling months 6 HF Fuel source for heating system (EL/NG/HO) 7 EFFH Efficiency of heating system -- 8 EFFC Efficiency of cooling system --
HF = EL kg/kWh HF = NG kg/m3
9
CO2EMHF Emission factor for HF heating fuel in PROV province HF = HO kg/L
10 CO2EMEL Emission factor for electricity in PROV province kg/kWh 11 LY Life of new refrigerator Years
HF=EL $/kWh HF=NG $/m3
12 PHF Price of heating fuel
HF=HO $/L
13 PEL Price of electricity $/kWh 14 FC First cost $ 15 i Interest rate % 16 g Average annual rate of growth in energy prices % 17 PCO2 Price of CO2 emission $/1000kg
Set defaults: LY to LY_DEF, PHF to PHF_DEF(HF, PROV), PEL to PHF_DEF(HF=EL, PROV),
i to i_DEF, PCO2 to PCO2_DEF, CO2EMHF to CO2EMHF_DEF(HF,PROV),
CO2EMEL to CO2EMHF_DEF(HF=EL, PROV)
IF AECC<2A-1> not answerable, THEN
92
Ask YEARC<2B-1>, VC<2B-2>, DFRSTC<2B-3>
IF DFRSTC <2B-3> = Auto THEN Ask FZRC <2B-4>
Look up EFC from table 3-6 using YEARC, DFRSTC, and FZRC
ADJVC = VC x (0.66 + (1-0.66) x 1.63)
Set AECC = 365 x ADJVC ÷ EFC
END IF
IF AECN <3A-1> not answerable, THEN
Ask VN <3B-1>, CATN<3B-2>, ESTARN<3B-3>
ADJVN = VN x (0.66 + (1-0.66) x 1.63)
Lookup energy consumption limit formula from table 3-7 using CATN
Calculate ECLN using energy consumption limit formula and ADJVN
IF ESTARN = Yes THEN
Set AECN = ECLN x 0.85
ELSE Set AECN = ECLN
END IF
END IF
ΔAEC = AECC – AECN
HES = -ΔAEC x (NHM /12) x CONVFkBTU/kWh
HFS = HES ÷ HEHF(HF) ÷ EFFH
CES = ΔAEC x (NCM /12) x CONVFkBTU/kWh
CFS = CES ÷ CONVFkBTU/kWh ÷ EFFC
CO2SAVEL = (ΔAEC + CFS) x CO2EMEL
CO2SAVHF = HFS x CO2EMHF
CO2SAVTOT = CO2SAVEL + CO2SAVHF
L_CO2SAV = CO2SAVTOT x LY
ADSEL = (ΔAEC + CFS) x PEL
ADSHF = HFS x PHF
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ADSCO2 = CO2SAVTOT ÷ 1000 x PCO2
ADSTOT = ADSEL + ADSHF + ADSCO2
°i = (1+i)÷(1+g) - 1
NPV = -FC + ADSTOT x (P/A, g, °i , LY)
Term Definition Units Value of Constant
LY_DEF Default value for life of new refrigerator years Table 3-3 HF = EL $/kWh HF = NG $/m3 PHF_DEF
(HF,PROV) Default value for price of HF in PROV province: Lookup from table 3-1 HF = HO $/L
table 3-1
i_DEF Default value for interest rate % 4.00 PCO2_DEF Default value for price of CO2 emission $/1000kg 0
HF = EL kg/kWh table 3-2 HF = NG kg/m3 1.89 CO2EMHF_DEF
(HF,PROV) Default value of emission factor for HF heating fuel in PROV province HF = HO kg/L 3.124
EFC Current refrigerator: shipment weighted energy factor ft3/kWh -- ADJVC Current refrigerator: adjusted volume ft3 -- ADJVN New refrigerator: adjusted volume ft3 -- ECLN New refrigerator: energy consumption limit value kWh/year -- ΔAEC Change in annual energy consumption from switching kWh/year -- HES Heat energy saving kBTU/year --
HF = EL kWh/year HF = NG m3/year
HFS Heating fuel saving HF = HO L/year --
CONVFkBTU/kWh Conversion factor: kWh to kBTU kBTU/kWh 3.4
HF = EL kBTU/kWh 1.0 HF = NG kBTU/m3 35.5
HEHF(HF) Heat energy of HF heating fuel HF = HO kBTU/L 39.6 CES Cooling energy saving kBTU/year -- CFS Cooling fuel saving kWh/year --
CO2SAVEL Saving in CO2 emission from reduction in electricity consumption kg/year --
CO2SAVHF
Saving in CO2 emission from reduction in HF consumption kg/year --
CO2SAVTOT Total annual saving in CO2 emission kg/year
L_CO2SAV Total saving in CO2 emission over lifetime of new refrigerator kg --
ADSEL Annual dollar saving from reduction in EL consumption $/year -- ADSHF Annual dollar saving from reduction in HF consumption $/year -- ADSCO2 Annual dollar saving from reduction in CO2 emission $/year -- ADSTOT Total annual dollar saving $/year -- NPV Net present value $ -- (P/A, i, LY) Factor to convert annuity at interest rate i, over LY
years to present value -- --
94
Notes on Input Questions
AECC Listed on EnerGuide Label
YEARC Available from manufacturer by providing current refrigerator’s serial number
VC Listed on the back of the refrigerator, user manual, and/or manufacturer’s website
DFRSTC Listed on the back of the refrigerator, user manual, and/or manufacturer’s website
FZRC Selected by user to describe the refrigerator’s design
AECN Listed on EnerGuide Label
VN Listed on the back of the refrigerator, user manual, and/or manufacturer’s website
CATN Selected by user from a list of general categories describing the refrigerator’s design
ESTARN Listed on the back of the refrigerator, user manual, and/or manufacturer’s website
Sample Calculation
# Term Input Questions Units Sample Input
1 PROV What province do you live in? -- ON 2A-1 AECC Current refrigerator: annual energy consumption
from EnerGuide Label kWh/year --
2B-1 YEARC Current refrigerator: year of purchase -- 1994 2B-2 VC Current refrigerator: volume of refrigerator ft3 18.5 2B-3 DFRSTC Current refrigerator: manual, auto defrost, or
don’t know -- Don’t Know
2B-4 FZRC Current refrigerator: freezer is at top or side-by-side -- --
3A-1 AECN New refrigerator: annual energy consumption from EnerGuide Label kWh/year --
3B-1 VN New refrigerator: volume of refrigerator (cu. Ft.) ft3 18.5 3B-2 CATN New refrigerator: category type (1 – 18) -- 5 3B-3 ESTARN New refrigerator: is it energy star certified? -- Yes
4 NHM Number of months of heating months 6 5 NCM Number of months of cooling months 3 6 HF Fuel source for heating system (EL/NG/HO) NG 7 EFFH Efficiency of heating system -- 0.90 8 EFFC Efficiency of cooling system -- 2.94 9
CO2EMHF Emission factor for HF heating fuel in PROV province HF = NG kg/m3 1.89
10 CO2EMEL Emission factor for electricity in PROV province kg/kWh 0.18 11 LY Life of new refrigerator Years 10 12 PHF Price of heating fuel HF=NG $/m3 0.30
95
13 PEL Price of electricity $/kWh 0.078 14 FC First cost $ 1300 15 i Interest rate % 4.00 16 g Average annual rate of growth in energy prices % 5.82 17 PCO2 Price of CO2 emission $/1000kg 0
IF AECC<2A-1> not answerable, THEN
Ask YEARC<2B-1>, VC<2B-2>, DFRSTC<2B-3>
IF DFRSTC <2B-3> = Auto THEN Ask FZRC <2B-4>
Look up EFC from table using YEARC, DFRSTC, and FZRC: EFC = 11.19
ADJVC = VC x (0.66 + (1-0.66) x 1.63) = 18.5 x (0.66 + (1-0.66) x 1.63) = 22.5
Set AECC = 365 x ADJVC ÷ EFC = 365 x 22.5 ÷ 11.19 = 731 kWh/year
END IF
IF AECN <3A-1> not answerable, THEN
Ask VN <3B-1>, CATN <3B-2>, ESTARN <3B-3>
ADJVN = VN x (0.66 + (1-0.66) x 1.63) = 18.5 x (0.66 + (1-0.66) x 1.63) = 22.5
Lookup energy consumption limit formula from table using CATN: 4.60 AV + 459.0
Calculate ECLN using energy consumption limit formula and ADJVN:
ECLN = 4.60 x 22.5 + 459 = 562
IF ESTARN = Yes THEN
Set AECN = ECLN x 0.85 = 562 x 0.85 = 476 kWh/year
ELSE Set AECN = ECLN
END IF
END IF
ΔAEC = AECC – AECN = 731 – 476 = 255 kWh/year
HES = -ΔAEC x (NHM /12) x CONVFkBTU/kWh = -255 x (6/12) x 3.4 = -433 kBTU/year
HFS = HES ÷ HEHF(HF) ÷ EFFH = -433 ÷ 35.5 ÷ 0.90 = -13.5 m3/year
CES = ΔAEC x (NCM /12) x CONVFkBTU/kWh = 255 x (3/12) x 3.4 = 216 kBTU/year
CFS = CES ÷ CONVFkBTU/kWh ÷ EFFC = 216 ÷ 3.4 ÷ 2.94 = 21.6 kWh/year
96
CO2SAVEL = (ΔAEC + CFS) x CO2EMEL = (255 + 21.6) x 0.18 = 49.8 kg/year
CO2SAVHF = HFS x CO2EMHF = -13.5 x 1.89 = -25.6 kg/year
CO2SAVTOT = CO2SAVEL + CO2SAVHF = 49.8 - 25.6 = 24.1 kg/year
L_CO2SAV = CO2SAVTOT x LY = 24.1 x 10 = 241 kg
ADSEL = (ΔAEC + CFS) x PEL = (255 + 21.6) x 0.078 = $21.6/year
ADSHF = HFS x PHF = -13.5 x 0.30 = $-4.07/year
ADSCO2 = CO2SAVTOT ÷ 1000 x PCO2 = 24.1 ÷ 1000 x 0 = 0
ADSTOT = ADSEL + ADSHF + ADSCO2 = 21.6 - 4.07 + 0 = $17.5/year
°i = (1+i)÷(1+g) - 1 = (1+0.04)÷(1+0.0582) - 1 = -0.0172 = -1.72%
NPV = -FC + ADSTOT x (P/A, g, °i , LY) = -1300+17.5 x(P/A,5.82%,-1.72%, 10) = $-416.84
97
Chapter 4 Calculator Main Module
In order for the calculator to function as one unit its algorithm must contain a module that
handles the operation of the 7 modules that calculate the saving from the 7 upgrades defined in
the last chapter. In many programming languages, C++ for example, this is called the ‘main’
module and the algorithm of this main module is what is described in this chapter.
Upon close inspection of the questions asked in the 7 modules, it was seen that some of the
questions asked were common to a few modules and some were even common to all modules.
Therefore, a matrix of all questions asked in the 7 modules was complied in order to determine
which questions are actually common to more than one module. These common questions need
only be asked once to limit redundancy. Table 4-1 shows the complied matrix. The questions
are sorted to show the most common questions first. It can be seen that seven questions i, g,
PCO2, PROV, CO2EMHF, HF, PHF are common to all upgrade modules. The questions FC and LY
have been shaded out in the table and left out of the analysis because although the same
variable name is used to represent the question of price and life in years in all the modules,
they actually represent different unique questions for each module and the answer to the
questions for one module cannot be used in any other module. The variables for all other
questions do represent one common question whose answer can be shared. Next, it can be
seen that there is 1 question that is common to 4 of the modules, 4 questions that are common
to 3 modules and so on. However, it can also be seen that there are a lot of questions that are
unique to only one module.
It is important that the number of questions required by an online calculator not be too onerous
since users surfing the web typically have short attention spans [SYNAX]. The bottom of the
table shows a compilation of the total number of variables used in each module, the minimum
number of questions that should be answered for each module to generate a result, and the
98
maximum number of questions that can ever be answered to generate a response. To arrive at
a count of the minimum number of questions, all questions whose values can be default were
excluded from the count, and when the algorithm forked into numerous paths, the path that
required the least questions to be answered was taken. On the other hand, for the maximum
number of questions the opposite was done: all the defaulted questions were included in the
count, and paths that asked the most number of questions were taken. It can be seen that the
furnace and heat pump modules require the least amount of effort needing only 6 answers each
at the minimum, whereas the window module require the most at 14 answers at the minimum.
It seems that answering between 6 to 14 questions per upgrade module should be an
acceptable number of questions.
Table 4-1 Matrix of questions
Module # 1 2 3 4 5 6 7
# Furnace Heat Pump
Prog. Therm. Insulation Window Lighting Refrigerator Freq.
1 FC 1 1 1 1 1 1 1 7
2 i 1 1 1 1 1 1 1 7 3 g 1 1 1 1 1 1 1 7
4 PCO2 1 1 1 1 1 1 1 7
5 PROV 1 1 1 1 1 1 1 7
6 CO2EMHF 1 1 1 1 1 1 1 7
7 HF 1 1 1 1 1 1 1 7
8 PHF 1 1 1 1 1 1 1 7
9 LY 1 1 1 1 1 1 6
10 EFFH 1 1 1 1 4
11 CO2EMEL 1 1 1 3
12 NHM 1 1 1 3
13 PEL 1 1 1 3
14 ACHF_C 1 1 1 3
15 EFFC 1 1 2
16 NCM 1 1 2
17 AFUEC 1 1 2
18 AFUEN 1 1
19 ACEL_C 1 1
20 HCOPN 1 1
21 HCOPc 1 1
22 HSYSC 1 1
23 HDT_WD 1 1
99
24 HDT_WE 1 1
25 HNT_WD 1 1
26 HNT_WE 1 1
27 TDT 1 1
28 TNORM 1 1
29 TNT 1 1
30 A 1 1
31 HDD 1 1
32 RSIA 1 1
33 RSIC 1 1
34 AFL 1 1
35 AW 1 1
36 AWTOT 1 1
37 CITY 1 1
38 L75_C 1 1
39 L75_N 1 1
40 ORNT 1 1
41 SHGCC 1 1
42 SHGCN 1 1
43 UC 1 1
44 UN 1 1
45 ADU 1 1
46 LH 1 1
47 PWCF 1 1
48 PWIL 1 1
49 AECC 1 1
50 AECN 1 1
51 CATN 1 1
52 DFRSTC 1 1
53 ESTARN 1 1
54 FZRC 1 1
55 VC 1 1
56 VN 1 1
57 YEARC 1 1 Total #
Variables 12 17 17 14 22 18 24 --
Min # Questions 6 6 11 8 14 10 9 --
Max # Questions 12 13 17 14 22 18 24 --
100
Finally, the algorithm of the main module would look somewhat like this:
1. Ask the 7 most common questions (represented by the variables i, g, PCO2, PROV,
CO2EMHF, HF, PHF) and store the answers in those variables. Ask PROV and HF first
because other variables could be defaulted from the answers to these two questions.
2. Ask which of the 7 upgrades is of interest
3. Compile the list of questions for each of the selected upgrade scenarios:
ADD EFFH to the list IF any of modules 4 – 7 selected
ADD CO2EMEL to the list IF any of modules 2, 6, or 7 selected
ADD NHM to the list IF any of modules 5 – 7 selected
ADD PEL to the list IF any of modules 2, 6, or 7 selected
ADD ACHF_C to the list IF any of modules 1 – 3 selected
ADD EFFC to the list IF any of modules 6 or 7 selected
ADD NCM to the list IF any of modules 6 or 7 selected
ADD AFUEC to the list IF any of modules 1 or 2 selected
IF module 1 selected ADD AFUEN to the list
IF module 2 selected ADD variables 19 22 to the list
IF module 3 selected ADD variables 23 29 to the list
IF module 4 selected ADD variables 30 33 to the list
IF module 5 selected ADD variables 34 44 to the list
IF module 6 selected ADD variables 45 48 to the list
IF module 7 selected ADD variables 49 57 to the list
4. Ask the questions in the complied list and store answers in variables
5. Invoke algorithms (given in chapter 3) for the selected upgrade scenarios using the
answers for the questions asked
6. Return results for the invoked algorithms.
101
Chapter 5 Results and Discussion
In this section several cases are presented to show how the calculator can be valuable to the
user. First, a section is presented to demonstrate the drastic effect that changing even one
variable has on the calculation. This is meant to show that the decision to perform an upgrade
cannot be taken in the abstract but requires knowledge of very specific information. Second,
the effect of future market and regulatory changes are studied. In particular, the effect of fuel
prices and the taxation of CO2 emissions are examined.
5.1 Impact of changing a single variable
In all of the following cases, actual data was used to demonstrate that changing the specifics of
the case by just one variable can lead to a complete reversal of the findings. These examples
demonstrate that it is not possible to draw general rules about which efficiency upgrades are a
good idea, contrary to what manufacturers, governments, and policymakers like to claim. They
demonstrate that the same upgrade can be beneficial in one specific case and not in another
with the difference between the specifics being quite small.
102
Cost-effectiveness of upgrading FURNACE efficiency
This case demonstrates how the net present value of upgrading to a higher-efficiency furnace
can change from a positive value to a negative value (indicating that the project is not cost-
effective) simply by increasing the efficiency value of the current furnace. This means that the
upgrade project cannot be cost effective if the efficiency of the current furnace is not low
enough. This seems logical since not enough heating fuel will be saved annually if there is not a
substantial increase in furnace efficiency. However, this essential decision enabling information
could not have been known without performing the calculation using the calculator’s algorithm
and without knowing the specific information required for the calculator.
Variable Input Questions Units Case A Case B PROV What province do you live in? -- ON
HF What heating fuel does your furnace use? -- NG
ACT_C Current: annual total household HF consumption m3/year 3,600
MCNHM_C Current: average monthly HF consumption in non-heating months m3/month 50
AFUEC AFUE of Current % 80% 85% AFUEN AFUE of New % 90% LY Life years 18 PHF Price of heating fuel $/m3 0.30 FC First cost of new furnace $ 1,300.00 i Interest rate % 4%
g Average annual rate of growth in energy prices % 5.82
PCO2 Price of CO2 emission $/1000kg 0 Output
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year 630.00 315.00
L_CO2SAV Total saving in CO2 emission over lifetime of new furnace kg 11,340.00 5,670.00
ADSTOT Total annual dollar saving $/year 100.00 50.00 NPV Net present value $ 713.91 -293.05
103
Cost-effectiveness of upgrading HEAT PUMP efficiency
In this example, raising the electricity price raises the net present value of the upgrade
significantly from a large negative value to a positive one making the investment cost effective.
An electricity price of $0.10/kWh may seem high in Quebec but it is not uncommon in Alberta
or Nova Scotia as shown in table 3-1. Furthermore, electricity from some renewable sources
such as solar typically costs much more than from conventional sources so if for instance this
household decides to use solar electricity, the upgrade project that was not cost-effective at the
lower electricity price becomes much more reasonable.
Variable Input Questions Units Case A Case B PROV What province do you live in? -- QB HSYSC What is your current heating
system? (Furnace OR Heat Pump) -- Heat Pump
ACEL_C Annual electricity consumption for heating kWh/year 10,000
HCOPC Heating COP – current system -- 3.0 HCOPN Heating COP – NEW heat pump -- 5.0
CO2EMEL Emission factor for EL for PROV province kg/kWh 0.006
LY Life of new heat pump years 15 FC First cost $ $4000 PEL Price of electricity (EL) $/kWh 0.053 0.10 i Interest rate % 4%
g Average annual rate of growth in energy prices % 5.82
PCO2 Price of CO2 emission $/1000kg 0 Output
CO2SAVEL Saving in CO2 emission from reduction in EL consumption kg/year 24.00
L_CO2SAV Total saving in CO2 emission over lifetime of new heat pump kg 360.00
ADSTOT Total annual dollar saving $/year 212.00 400.00 NPV Net present value $ -1,328.61 1,044.47
104
Cost-effectiveness of upgrading to a PROGRAMMABLE THERMOSTAT
Upgrading to a programmable thermostat is inherently not a risky investment because the first
cost is relatively low compared to the other upgrades (about $90 on average from table 2-1).
Nevertheless, this example shows how a very highly positive net present value upgrade can
turn into a less attractive proposition (although still positive). This would be the case for a
dwelling located in a more temperate climate where the dwelling’s heating fuel consumption is
much lower, but it is clearly visible that this is still a cost-effective upgrade even if it is not as
attractive as it is for a colder climate. It appears that the only way this upgrade can become
cost-ineffective is if the thermostat is installed but not programmed to setback temperatures at
all or not programmed to setback for long enough to save enough heating fuel to recover the
low capital cost. That can be quite rare.
Variable Input Questions Units Case A Case B PROV What province do you live in? -- ON TNORM Temperature without set-back °C 23 TNT Night-time temperature °C 20 TDT Daytime temperature °C 18 HNT_WD Weekday night-time set-back hours hours 8
HDT_WD Weekday daytime set-back hours hours 10
HNT_WE Weekend night-time set-back hours hours 9
HDT_WE Weekend daytime set-back hours hours 4
HF What fuel does your heating system use? (EL/NG/HO) -- NG
ACHF_C Current annual heating fuel consumption m3 3,000 1,000
CO2EMHF Emission factor for HF heating fuel in PROV province kg/m3 1.89
LY Life of thermostat Years 18 PHF Price of heating fuel $/m3 0.35 FC First cost $ 90.00 i Interest rate % 4%
g Average annual rate of growth in energy prices % 5.82
PCO2 Price of CO2 emission $/1000kg 0 Output
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year 469.80 156.60
L_CO2SAV Total saving in CO2 emission over lifetime of new thermostat kg 8456.40 2818.80
ADSTOT Total annual dollar saving $/year $87.00 $29.00 NPV Net present value $ 1,408.82 409.61
105
Cost-effectiveness of increasing BUILDING ENVELOPE INSULATION
This example is similar to the furnace example where the current situation is not bad enough to
make the upgrade cost effective. Changing the current insulation amount from 2 m2.K/W to 5
m2.K/W moves the net present value from a positive to a negative value. The calculator yet
again clearly delivers good value to the homeowner.
Variable Input Questions Units Case A Case B PROV What province do you live in? -- ON HDD Heating degree days K.days 3570 A Area of insulation m2 200 RSIC Current insulation RSI amount m2.K/W 2 5 RSIA Additional insulation RSI amount m2.K/W 7
HF What fuel does your heating system use? (EL/NG/HO) -- NG
EFF Efficiency of heating system % 0.90
CO2EMHF Emission factor for HF heating fuel in PROV province kg/m3 1.89
LY Life of new insulation Years 30 PHF Price of heating fuel $/m3 0.35 FC First cost $ 3,400 I Interest rate % 4.00
g Average annual rate of growth in energy prices % 5.82
PCO2 Price of CO2 emission $/1000kg 0 Output
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year 1,340.31 402.09
L_CO2SAV Total saving in CO2 emission over lifetime of new thermostat kg 40,209.26 12,062.78
ADSTOT Total annual dollar saving $/year 248.21 74.46 NPV Net present value $ 5,911.79 -606.46
106
Cost-effectiveness of upgrading WINDOW efficiency
This example shows the high dependence of the net present value on the price of fuel. Raising
the price of the heating fuel in the case raises the NPV out of the negative at $-508.79 to
$961.56. If an ‘average’ calculation was performed by an advisory body using the lower price of
natural gas, $0.43/m3, it would advise Montreal residents that upgrading the efficiency of their
windows is not cost-effective, however that conclusion would be flawed for any dwelling that
was buying natural gas at the higher $0.90/m3. As such the value of this calculator to the
individual homeowner is again demonstrated.
Variable Input Questions Units Case A Case B PROV What province do you live in? -- QB CITY Select what major city is closest to
you -- Montreal
ORNT Select the orientation of your window (N, NE, E, SE, S, SW, W, NW)
-- N
SHGCC What is the Solar Heat Gain Coefficient (SHGC) of your current window?
-- 0.16
UC What is the U of your current window? W/m2.K 3.00
AWTOT What is the total area of ALL windows in your house? m2 10
AFL What is the floor area of your house? m2 100 L75_C What is your current window’s air
leakage rate at a pressure differential of 75 Pa
m3/h 0
SHGCN What is the Solar Heat Gain Coefficient (SHGC) of your NEW window?
-- 0.43
UN What is the U of your new window? W/m2.K 1.31 L75_N What is your new window’s air
leakage rate at a pressure differential of 75 Pa
m3/h 0
AW Area of window m2 4.46 NHM How many months do you heat? months 8 HF What fuel does your heating system
use? (EL/NG/HO) -- NG
EFF Efficiency of heating system % 60%
CO2EMHF Emission factor for HF heating fuel in PROV province kg/m3 1.89
LY Life of window Years 15 PHF Price of heating fuel $/m3 0.43 0.90
107
FC First cost $ 1854 i Interest rate % 4.00
g Average annual rate of growth in energy prices % 5.82
PCO2 Price of CO2 emission $/1000kg 0 Output
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year 362.05
L_CO2SAV Total saving in CO2 emission over lifetime of new thermostat kg 5,430.73
ADSTOT Total annual dollar saving $/year 82.37 172.40 NPV Net present value $ -508.79 961.56
108
Cost-effectiveness of upgrading LIGHTING efficiency
Upgrading an ILB to a CFLB is largely regarded as a being a good idea with no down sides. This
example demonstrates, however, that in Case B where the power rating of the CFLB being
installed is slightly different from Case A the upgrade changed from a positive NPV to a
negative NPV. The power rating of the ILB for Case B was changed to reflect the true equivalent
rating that the 16 W CFLB replaces as suggested by the manufacturer. Similarly, the FC was
also changed to represent the actual price of a 16W CFLB on the market. In conclusion,
upgrading to a CLFB from and ILB is not always cost-effective.
Variable Input Questions Units Case A Case B PROV What province do you live in? -- QB PWCF Power rating of CFLB W 9 16 PWIL Equivalent power rating of ILB W 40 65 ADU Average daily usage hours 5 NHM Number of months of heating months 8 NCM Number of months of cooling months 2 HF Fuel source for heating system
(EL/NG/HO) NG
EFFH Efficiency of heating system -- 0.90
EFFC Efficiency of cooling system -- 2.94
CO2EMHF Emission factor for HF heating fuel in PROV province kg/m3 1.89
CO2EMEL Emission factor for electricity in PROV province kg/kWh 0.006
LH Life of CFLB hours 10,000 PHF Price of heating fuel $/m3 0.43 PEL Price of electricity $/kWh 0.053 FC First cost $ 3.99 14.98 i Interest rate % 4.00
g Average annual rate of growth in energy prices % 5.82
PCO2 Price of CO2 emission $/1000kg 0 Output
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year -7.23 -11.42
L_CO2SAV Total saving in CO2 emission over lifetime of new thermostat kg -39.60 -62.59
ADSTOT Total annual dollar saving $/year 1.44 2.28 NPV Net present value $ 3.91 -2.49
109
Cost-effectiveness of upgrading REFRIGERATOR efficiency
This example shows that when the new refrigerator that replaces one whose annual energy
consumption is high enough the project can be cost-effective. In Case A where the current
refrigerator consumes 731 kWh/year (1994 model) the upgrade have a negative NPV but when
in Case B the current refrigerator being replaced is a much older (1972) model that consumes
2139 kWh/year the project becomes a positive NPV. Thus, it cannot be said whether upgrading
a refrigerator is cost-effective or not in general.
Variable Input Questions Units Case A Case B PROV What province do you live in? -- ON AECC Current refrigerator: annual energy
consumption from EnerGuide Label kWh/year 731 2139
AECN New refrigerator: annual energy consumption from EnerGuide Label kWh/year 476
NHM Number of months of heating months 6 NCM Number of months of cooling months 3 HF Fuel source for heating system
(EL/NG/HO) NG
EFFH Efficiency of heating system -- 0.90
EFFC Efficiency of cooling system -- 3.82
CO2EMHF Emission factor for HF heating fuel in PROV province kg/m3 1.89
CO2EMEL Emission factor for electricity in PROV province kg/kWh 0.18
LY Life of new refrigerator Years 10 PHF Price of heating fuel $/m3 0.35 PEL Price of electricity $/kWh 0.078 FC First cost $ 599.00 i Interest rate % 4.00
g Average annual rate of growth in energy prices % 5.82
PCO2 Price of CO2 emission $/1000kg 0 Output
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year 23.26 151.68
L_CO2SAV Total saving in CO2 emission over lifetime of new thermostat kg 232.57 1516.75
ADSTOT Total annual dollar saving $/year 16.44 107.23 NPV Net present value $ -427.86 517.11
110
Effect on CO2 emissions of upgrading LIGHTING efficiency
When the electricity used to power lights is clean enough (low CO2 emission factor) upgrading
an ILB to a CFLB can actually lead to an increase in CO2 emissions, as this example
demonstrates. This is because the reduction in heat produced by lighting after the upgrade has
to be compensated by burning heating fuel with a much higher CO2 emission factor than the
clean electricity. That would be the case for a dwelling in Manitoba where CO2 emission factor
for electricity is only 0.010 kg/kWh compared to 0.930 kg/kWh in Alberta, which also uses
natural gas for space heating. The input questions asking for prices (fuel prices, first cost, etc…)
have been removed because they do not affect CO2 emission savings values. Thus, it is not
always environmentally beneficial to change an ILB to a CFLB.
Variable Input Questions Units Case A Case B PROV What province do you live in? -- AL MN PWCF Power rating of CFLB W 9 PWIL Equivalent power rating of ILB W 40 ADU Average daily usage hours 5 NHM Number of months of heating months 9 NCM Number of months of cooling months 1 HF Fuel source for heating system
(EL/NG/HO) NG
EFFH Efficiency of heating system -- 0.90
EFFC Efficiency of cooling system -- 2.94
CO2EMHF Emission factor for HF heating fuel in PROV province kg/m3 1.89
CO2EMEL Emission factor for electricity in PROV province kg/kWh 0.930 0.010
LH Life of CFLB hours 10,000 Output
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year 45.57 -7.95
L_CO2SAV Total saving in CO2 emission over lifetime of new thermostat kg 249.71 -43.57
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Effect on CO2 emissions of upgrading REFRIGERATOR efficiency
This example shows that similar to the previous example of upgrading lighting the upgrading of
refrigerator efficiency can also increase CO2 emissions. Like the previous example, this example
uses a low carbon emission source of electricity to show this. Thus, upgrading a refrigerator
may or may not be environmentally beneficial depending on the specifics.
Variable Input Questions Units Case A Case B PROV What province do you live in? -- ON MN AECC Current refrigerator: annual energy
consumption from EnerGuide Label kWh/year 731
AECN New refrigerator: annual energy consumption from EnerGuide Label kWh/year 476
NHM Number of months of heating months 6 NCM Number of months of cooling months 3 HF Fuel source for heating system
(EL/NG/HO) NG
EFFH Efficiency of heating system -- 0.90
EFFC Efficiency of cooling system -- 3.82
CO2EMHF Emission factor for HF heating fuel in PROV province kg/m3 1.89
CO2EMEL Emission factor for electricity in PROV province kg/kWh 0.180 0.010
LY Life of new refrigerator Years 10 Output
CO2SAVHF Saving in CO2 emission from reduction in HF consumption kg/year 23.26 -22.93
L_CO2SAV Total saving in CO2 emission over lifetime of new thermostat kg 232.57 -229.27
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Effect on CO2 emissions of all other upgrades
The effect on CO2 emissions for all other upgrades (furnace efficiency upgrade, heat pump
efficiency upgrade, thermostat, building insulation, and window upgrade) can only be the
reduction in emissions. That is because, in contrast with the upgrading of lights and
refrigerators, the other upgrades do not cause an increase in consumption of one form of
energy while reducing that of another. Upgrading to a CFLB for example cuts electricity
consumption, but raises consumption of the heating fuel, and if this heating fuel has a higher
carbon emission factor than electricity in the dwelling’s region and there is a substantial heating
requirement this upgrade leads to an increase in CO2 emission. However, the upgrade of a
furnace (to consider an example of the aforementioned other upgrades) does not increase the
consumption of any form of energy; it only reduces consumption of the heating fuel.
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5.2 Effects of future regulatory and market changes
In this section the value of the calculator is demonstrated by studying the results it generates
when various fuel prices and CO2 emission prices are entered as inputs. These prices are meant
to simulate the effects of future market scenarios (the rise or fall of fuel prices) and regulatory
scenarios (the imposition of a carbon tax) on the cost-effectiveness of the particular upgrades
under study.
The upgrade of lighting to CFLBs at 2 different power ratings and for dwellings located in 3
different provinces was studied. This resulted in 6 different cases as shown in table 5-1. The
three shaded variables were the ones that were varied independently one at a time for all 6
cases. When the shaded variable was not being varied the values shown in the table were the
values used by default. These values reflect actual market prices for the province involved
(from table 3-1).
Table 5-1 Inputs for 6 cases to study effects of regulatory and market changes Variable Case 1 Case 2 Case 3 Case 4 Case 5 Case 6 PROV ON ON AL AL QB QB PWCF 16 9 16 9 16 9 PWIL 65 40 65 40 65 40 ADU 5 5 5 5 5 5 NHM 6 6 8 8 8 8 NCM 3 3 2 2 2 2 HF NG NG NG NG NG NG EFFH 0.90 0.90 0.90 0.90 0.90 0.90 EFFC 2.94 2.94 2.94 2.94 2.94 2.94 CO2EMHF 1.89 1.89 1.89 1.89 1.89 1.89 CO2EMEL 0.180 0.180 0.930 0.930 0.006 0.006 LH 10,000 10,000 10,000 10,000 10,000 10,000 PHF 0.35 0.35 0.22 0.22 0.43 0.43 PEL 0.078 0.078 0.100 0.100 0.053 0.053 FC 14.98 3.99 14.98 3.99 14.98 3.99 i 4.00 4.00 4.00 4.00 4.00 4.00 PCO2 0 0 0 0 0 0
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Figure 5-1 shows the net present values for all 6 upgrade cases using various natural gas prices
as input. It can be seen that if the natural gas price is as low as $0.35/m3 all upgrade cases
have non-negative net present values whereas at a natural gas price of $1.20/m3 almost all
upgrade cases are not cost-effective. Considering that Ontario, Alberta, and British Columbia
have unit natural gas prices of $0.35, $0.22, $0.96 respectively (table 3-1) it can be seen that
the prices simulated in figure 5-1 are all possible actual, non-hypothetical market prices for
natural gas. It can thus be concluded that simply the price of natural gas itself can change the
attractiveness of such an upgrade investment. The value of the calculator to a homeowner is
then manifested by the ability of the calculator to generate net present values for any range of
natural gas prices that the homeowner may believe to exist in the future (typically over the life
of the new installation). In the absence of such ability the homeowner would be able to
visualize the full extent of how risky or riskless his/her investment in the upgrade may be. It is
unfortunate though that it is not possible to predict future fuel prices without uncertainty and
thus the future price will have to be relegated to the homeowner’s best belief and judgement at
the time when the investment is contemplated.
-40
-30
-20
-10
0
10
20
30
40
$0.00 $0.20 $0.40 $0.60 $0.80 $1.00 $1.20 $1.40
Natural Gas Price ($/m3)
Net
Pre
sent
Val
ue
Case 1: ON, 65-->16 W Case 2: ON, 40-->9 W Case 3: AL, 65-->16 WCase 4: AL, 40-->9 W Case 5: QB, 65-->16 W Case 6: QB, 40-->9 W
Figure 5-1 Net present value results for changing natural gas prices
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Figure 5-2 shows the net present value for the 6 upgrade cases with various input of electricity
prices. Similar to the scenario for natural gas, all upgrade cases can turn-up a negative net
present value (at $0.030/kWh) or all can turn-up a positive one (at $0.060/kWh) simply with
the change in electricity prices. Putting these prices into context by noting that current
electricity prices can vary from $0.053/kWh in Quebec to $0.110/kWh in Nova Scotia it can be
seen that the electricity prices simulated are not too far from current market prices and are
thus not too far from being attainable in the future. Yet again the value of the calculator lies in
its ability to give the user the option of changing the specified electricity price so that he/she is
able to visualize its effect on the cost-effectiveness of the upgrade.
-30-20-10
0102030405060
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14
Electricity price ($/kWh)
Net
Pre
sent
Val
ue
Case 1: ON, 65-->16 W Case 2: ON, 40-->9 W Case 3: AL, 65-->16 WCase 4: AL, 40-->9 W Case 5: QB, 65-->16 W Case 6: QB, 40-->9 W
``
Figure 5-2 Net Present value results for changing electricity prices
116
Figure 5-3 shows the net present value for the 6 upgrade cases with both electricity and natural
gas prices being varied simultaneously. The input electricity prices were taken to be as they
were for figure 5-2. The input natural gas price was then calculated by changing the base
natural gas price by the same percentage as the electricity price was changed from its base
price. This is a reasonable approximation since both energy prices vary similarly. This particular
simulation was performed to see the combined effect of energy price changes on the NPV and
since increasing natural gas prices have a negative effect on the NPV whereas increasing
electricity prices have a positive effect, it was interesting to see which price change dominated.
As can be seen in the figure, the effect of electricity price dominates since the NPV increases in
all the 6 cases. This is encouraging because it shows that as general energy prices increase
upgrading lights will become more financially beneficial.
-20
-10
0
10
20
30
40
50
60
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14
Electricity price ($/kWh)
Net
Pre
sent
Val
ue
Case 1: ON, 65-->16 W Case 2: ON, 40-->9 W Case 3: AL, 65-->16 WCase 4: AL, 40-->9 W Case 5: QB, 65-->16 W Case 6: QB, 40-->9 W
``
Figure 5-3 Net present values for simultaneous changes in electricity & natural gas prices
117
Figure 5-4 demonstrates the NPVs resulting from various CO2 emission prices for the 6 upgrade
cases. It can be seen that no general trend can be extrapolated from the produced results.
Some cases that start out being positive at a zero emission price continue to become more
positive as the price of emission is increased, Case 5 that starts out negative continues to grow
more negative, and Case 6 that starts out positive actually becomes less positive and then
almost zero as the carbon emission price increases. This leads us to conclude that there is a
complicated play between relationships that raise the NPV and those that lower it as the carbon
emission prices rises. The calculator then is a good tool to enable homeowners to see the effect
of possible future carbon taxes on the cost-effectiveness of their specific upgrade.
-10.00
0.00
10.00
20.00
30.00
40.00
50.00
60.00
0 0.5 1 2 5 10 20 30 50
CO2 emission price ($/1000kg CO2)
Net
Pre
sent
Val
ue
Case 1: ON, 65-->16 WCase 2: ON, 40-->9 WCase 3: AL, 65-->16 WCase 4: AL, 40-->9 WCase 5: QB, 65-->16 WCase 6: QB, 40-->9 W
Figure 5-4 Net present value results for changing CO2 emission prices
118
Chapter 6 Conclusions
This thesis documented the development of a residential energy conservation calculator for a
large Canadian FSI. The goals of the project (calculating the financial and environmental
impacts residential upgrades, and the impact of future energy prices and carbon emission prices
on the cost-effectiveness of the project) were met by designing the algorithm for the calculator
software that can be programmed into a user-friendly web application accessible by the FSI’s
customers over the Internet. For future work, the FSI is advised to program the web-application
using the algorithms provided in this report and to build helpful notes using the “Notes on Input
Questions” provided.
For each upgrade project, the algorithm shows how the energy saved by the upgrade, the
carbon emissions reduced, and the amount of money saved as a result of the upgrade are
calculated. The algorithms were based on calculation procedures discovered through research of
accessible resources. Particular attention was paid to researching and detailing how a novice
user of the calculator would go about obtaining the information required to answer the
questions asked by the algorithm.
The value of the calculator was demonstrated by showing that upon varying just one of the
numerous inputs required by the calculator the results might be significantly changed: highly
cost-effective investments can become money loosing ventures, and some upgrades that
reduce carbon emissions can actually end up generating more CO2. This showed that it is not
good enough for a homeowner to rely simply on general rules-of-thumb measures established
using average inputs that prescribe which home upgrades are or are not financially and
environmentally beneficial. The value of the calculator was demonstrated by documenting its
ability to generate results based on potential future fuel prices and taxes on carbon emissions.
119
Glossary of Acronyms & Terms
ΔT temperature difference °C degrees Celsius °F degrees Fahrenheit A cross-sectional area AEC annual energy consumption AFUE Annual Fuel Utilization Efficiency AL Alberta AS annual saving ASHP air source heat pump AV adjusted volume BC British Columbia CFLB compact fluorescent light bulb CO2 carbon dioxide CREEM Canadian Residential End-use Model CSA Canadian Standards Association EF energy factor FC first cost FSI financial services institution ft2 square feet GHG greenhouse gas GJ gigajoules GSHP ground source heat pump HCOP heating coefficient of performance HDD heating degree days HES Home Energy Saver HOT2000 building energy simulation software HSPF heating seasonal performance factor HVAC heating ventilation and air-conditioning ILB incandescent light bulb K Kelvin kBTU kilo British thermal unit kWh kilowatt-hour LB Labrador LBNL Lawrence Berkley National Laboratory lbs pounds – unit of weight m2 square meter m3 cubic meter MJ megajoules MN Manitoba NB New Brunswick NFL New Foundland NPV net present value NRCan Natural Resources Canada NS Nova Scotia NU Nunavut NWT Northwest Territories
120
ON Ontario PEI Prince Edward Island PV present value QB Quebec RSI thermal resistance expressed in SI units SHGC solar heat gain coefficient SI standard international SK Saskatchewan U heat transfer coefficient W watt YK Yukon
121
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