Demystifying Home Energy Use

May 21, 2015Central Brevard Library

Cocoa, Florida

Janet McIlvaine and David BealBuildings Research Division

Research Analystsjanet@fsec.ucf.edu david@fsec.ucf.edu

(Please include “home energy” in your subject line.)

FSEC established in 1975 by Florida Legislature 30 years of energy efficiency research for Homes

and Buildings for Florida Certifications, Training, & K-12 STEM Teachers

Florida Solar Energy Center

(FSEC)

1679 Clearlake Rd Cocoa, FL 32922Corner of Michigan & Clearlake on the UCF Cocoa

Campus

Measured building energy use savings Develop guidelines for contractors Does it work in the real world?

Real houses and full scale residential & commercial labs

Florida Solar Energy Center

Buildings Research Scope

Florida Solar Energy CenterBuildings Research Scope

Investigate How Houses Use Energy Goal: Minimize Energy Use Without

Sacrificing Health, Safety, Durability, or Comfort

Do no harm Combustion safety caution

Researchers Conclude: It’s Complicated!Use free resources at www.fpl.com and consult a RESNET certified home energy rater and/or an Energy Star certified heating & cooling contractor

$1,885Annually

$0Annually

Florida Solar Energy Center

Buildings Research Basics

Department of Energy Goal: zero energy homes Produced power ≥ Needed power - annually Maintain or improve occupant safety and

comfort, indoor air quality, & building durability

Florida Solar Energy Center

Zero Energy Home Basics

Off-the-grid or grid-tied (above) zero energy houses offset power use with power produced by solar electric panels. Excess sold to the utility.

Ph

oto

Cre

dit

: E

nerg

y F

arm

Au

stra

liah

ttp

://w

ww

.en

erg

yfa

rm.c

om

.au

/wp

-con

ten

t/u

plo

ad

s/2

01

0/0

8/g

rid

_dia

gra

m.p

ng

Is Zero Energy practical for new homes? Yes - see case studies Engineered set of improvements & detailing to prevent failures

Zero Energy by design: HERS Index score ≤ 0 (with Solar) HERS Index score = ~55 (w/o Solar)

Florida Solar Energy Center

Zero Energy New Homes

This Home Without Solar 55

Typicalnew FLhome

Is Zero Energy practical for existing homes? In research realm Carefully selected measures Time line complications Comprehensive plan to prevent failures

Florida Solar Energy Center

Zero Energy Existing Homes

Private Residence, 1959

Cocoa Beach, FL

Pre $754 Post $557 $377 v $278$377 v $278$377 v $278

Florida Solar Energy Center

Typical Projected Annual Energy Use for 70 Florida Homes

Retrofit Status

CondArea Ft2

Average

Day kWh

Average Day $

Average

Month $

Average

Year $

Average

Year $/Ft2

Before 1,365 ft2

40 kWh $ 5.16 $ 157 $ 1,885 $1.42

After 1,365 ft2

29 kWh $ 3.82 $ 116 $ 1,394 $1.05

Daily Average Use = 43 kWh, $5.16 = $154 Monthly

= $1,883 Annually = $1.79 per square foot/year

1050 ft2 , 3 BR, slab on grade, concrete block, ~1993 construction

Typical Residential Energy Use in Florida

Heating & Cooling 40.7%

Other 19.6%

Refrigerator 7.9%

Dryer 8.6%

Range 4.4% Water Heating 18.7%

Typical Residential Energy Use in Florida

Daily Average Use = 39.1 kWh, $4.69 = $141 Monthly

= $1,712 Annually = $1.05 per square foot/year

1627 ft2 , 3 BR, slab on grade, concrete block, 2003 construction

Typical Residential Measured Energy Use

Year Cond

Area

Ft2

AvgDay kWh

AvgDay

$

AvgMont

h$

AvgYear

$

AvgYear/Ft2

$

1993 1,050

43 $5.16 $154 $1,883

$1.79

2003 1,627

39.1 $4.69 $141 $1,712

$1.05

Typical Cooling Load

Energy Use in Florida

Building America Partnership for Improved Residential Construction

Decade Average Pre-retrofit HERS Index Scores

1970’s 132

1990’s 112

2000’s 107

1960’s 150 1980’s 125

15

ZeroEnergy

New HomeBefore Solar

Building America Partnership for Improved Residential Construction

HERS Index Examples

2000’s = 107

16

1960’s = 150

Solar Ready = 55Zero Energy = -6

How Low Can Existing Homes Go? Cost Effectively!

70 House Field Study of “Deep Energy Retrofits”30% HERS Index Improvement Goal

Nearly All Improvements Packages Predicted Positive Cash Flow

Partner map

Partnerships Map: http://goo.gl/5KnTau

Building America Partnership for Improved Residential Construction

Pre- & Post-Retrofit HERS IndicesExisting homes made as good as new!

18

TypicalNew FloridaHomes

Building America Partnership for Improved Residential Construction

Wide Variation in HERS Index Score Among Houses of Similar Age

TypicalNew FloridaHomes

Building America Partnership for Improved Residential Construction

• Existing Unoccupied Homes in Palm Bay, Florida• Pre-retrofit HERS Index score = 121• HERS Index score = 65 (46% improvement)

Florida Solar Energy CenterComprehensive Renovation

Foreclosed Home Rehab, 1973Palm Bay, FL

Building America Partnership for Improved Residential Construction

• Energy Retrofit Package– Replacement HVAC equipment – SEER 15, HSPF 8.5– Increase ceiling insulation to R38– Air sealing – ACH50 = 7.44 (average new 6)– Duct replacement & sealing – Qn = 0.07– Replacement Windows (U = 0.32, SHGC = 0.28)– Energy Star refrigerator– Replacement Water heater EF = 0.92– 90% CFL or Fluorescent Tube Lighting – Replacement Lighter shingle color– Efficient ceiling fans – 130W at medium speed

Florida Solar Energy CenterComprehensive Renovation

Building America Partnership for Improved Residential Construction

• Energy Retrofit Package– Total cost for energy related improvements = ~$24,000– INCREMENTAL cost =~$5,000 (out of $24,000)

Florida Solar Energy CenterComprehensive Renovation

% HERS Index Improvement 46%

Incremental Improvement Costs $5,013Additional Monthly Mortgage +$34

Monthly Energy Savings -$49Monthly Cash Flow +$15

Simple Payback (years) 8

Building America Partnership for Improved Residential Construction

70 House Deep Retrofit Field Study 13 Most Prevalent Key Strategies

13 Key Efficiency Strategies in Order of Prevalence

Deep Retrofits (n = 46)

Non-Deep Retrofits (n

= 24)

All Houses(n = 70)

1. At Replacement, Higher HVAC efficiency 96% 71% 87%

2. Additional ceiling insulation 93% 63% 83%

3. Whole-house air sealing (Reduced ACH50) 92% 77% 88%

4. Air distribution system sealing (reduced Qn,out) 86% 68% 80%5. At Replacement, Low-e windows or 6. Apply high perf. film

80% 46% 67%

7. At Replacement, ENERGY STAR® refrigerator 76% 71% 74%

8. At Replacement, Highest efficiency tank type water heater 70% 38% 59%

9. At Replacement, 30% more fluorescent fixtures/bulbs 52% 42% 49%

10. Programmable thermostat 48% 42% 46%

11. At Replacement, R-6 ducts 39% 13% 30%

12. At Replacement, Higher reflectivity exterior wall color 30% 8% 23%

13. At Replacement, Higher reflectivity roof shingles 30% 13% 24%

14. At Replacement, Higher efficiency ceiling fan(s) 15% 13% 14%

Building America Partnership for Improved Residential Construction

Cost Effective Efficiency Enhancements and Replacements

• Anytime, low-cost measures: • Behavior Modification• House sealing* (92% of the deep retrofits) • Duct sealing* (86%)• CFLs (52% increased CFL count by 30%+)• Programmable thermostat (48%)• New: Insulate hot water heater* & accessible hot water pipes

• Anytime, moderate-cost measures• Insulate ceiling to R-38 (93% insulated to R-30+)

*Heed combustion safety cautions. Contact Janet McIlvaine, 321-638-1434

24

Building America Partnership for Improved Residential Construction

• At replacement, no/low cost measures: (Higher efficiency choices at change-out)

• ENERGY STAR® appliances (76% of the deep retrofits)• Higher efficiency water heater (EF ≥ 0.92) (70%)

– Consider much bigger savings with heat pump water heater or solar or instantaneous gas

• Choose higher insulated (R-6) duct work (39%)• Choose lighter exterior colors when time to reroof (30%)• ...or paint exterior (30%)• ENERGY STAR® fans (15%)

25

Cost Effective Efficiency Enhancements and Replacements

Building America Partnership for Improved Residential Construction

• At replacement, moderate/high cost measures: (Higher efficiency choices at change-out)

• ≥15 SEER AC; Heat pump in Central FL (96% of the deep retrofits replaced ACs, 95% of those SEER ≥ 15)

• ENERGY STAR® windows or apply low SHGC film (80%)(SHGC ≤ 0.27; U-value ≤ 0.60)

26

Cost Effective Efficiency Enhancements and Replacements

Building America Partnership for Improved Residential Construction

• Behavior Modification– Maintain your central air conditioner

• Keep filter clean• Set fan to “auto” instead of “on”

– Set thermostat as high as you are comfortable and maintain ~5° higher when not at home

• Every 1° cooler = Approx 6% cooling energy

– Turn off ceiling fans when occupants are not present • (1 fan continuous oper. = approx $7/month)

– When washing in hot water, adjust the load selector to match the actual size of the load.

– Keep the lint filter in your dryer clean

Cost Effective Efficiency Enhancements and Replacements

It’s Complicated: Mix & Size ofEnd-Uses at Each Site Unique

Spam, spam, spam!Scam, scam, scam!Scram, scram, scram!

Attic Radiant BarrierSavings Claim = 40%

Insulation for Block Walls Savings Claim = 50%

Attic Radiant BarrierSavings Claim = 35%

Window ReplacementSavings Claim = 30%

Attic Radiant BarrierSavings Claim = 20%

Solar Panels (Electric )Savings Claim = 30%

Thank

You!