assessing your building energy costs: benefits of energy modeling to owners
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Keith Swartz of the Energy Center of Wisconsin presents Assessing Your Building Energy Costs: Benefits of Energy Modeling to Owners at the 2012 Chicago Energy Modeling Conference.TRANSCRIPT
Assessing Your Building Energy Costs:
Benefits of Energy Modeling to Owners
Keith SwartzEnergy Center of Wisconsin
ComEd New Construction ProgramNicor New Construction Program
Illinois ASHRAE Modeling ConferenceFebruary 14, 2012
Energy Modeling for Owners
Building Energy Model Basics
Reasons to do a Building Energy Model
Selecting an Energy Modeler
Information Exchange with the Modeler
Economic Analysis and Decision Making
Building Energy Model Basics A computer simulation that estimates
the energy use and energy cost of a building
Simple or complex Accounts for system interactions Existing or new building
Building Energy Model Basics
Limitations No program is perfect Many inputs are assumed Only an estimate Does not make decision for you
Energy Modeling for Owners
Building Energy Model Basics
Reasons to do a Building Energy Model
Selecting an Energy Modeler
Information Exchange with the Modeler
Economic Analysis and Decision Making
Why Do an Energy Model? Provide information for a decision
Often energy cost savings for potential upgrades
Prevent bad decisions based on bad hunches
Determine number of LEED® credits Documentation for tax credit Identify where your energy dollars
are going Estimate future energy use or cost
Why Not Do an Energy Model?
Low-energy building Small Simple
Energy not a concern Insufficient time in project schedule No local qualified energy modelers
Energy Modeling for Owners
Building Energy Model Basics
Reasons to do a Building Energy Model
Selecting an Energy Modeler
Information Exchange with the Modeler
Economic Analysis and Decision Making
Selecting an Energy Modeler
Where to find an energy modeler• Architectural firm• Engineering firm• Energy consulting firm (ESCO)• Sustainable building consultant• Independent modeling consultant• Utility
Be very specific in the contract
Selecting an Energy Modeler
What to look for in an energy modeler• Knowledge of buildings• Knowledge of the software used• Quality control procedures• ASHRAE certification as a Building Energy
Modeling Professional (BEMP)• Can generate energy saving ideas
Selecting an Energy Modeler
What to look for in an energy modeler• Able to communicate and summarize• Flexibility with deliverables• LEED modeling experience (if applicable)• Construction cost estimating (optional)• Financial analysis (optional)
Energy Modeling for Owners
Building Energy Model Basics
Reasons to do a Building Energy Model
Selecting an Energy Modeler
Information Exchange with the Modeler
Economic Analysis and Decision Making
Info Modeler Needs from You
Reason for doing the energy model Deliverable Location of the building People Lights Plugged in equipment HVAC systems
Info Modeler Needs from You
Building drawings Utility rates List of options to evaluate For existing buildings add
• As much detail as possible on the above items
• Past utility bills, 3 years• Submeter data (if any)
Info You Need from Modeler
Depends on why the model was done The deliverable
Info You Need from Modeler
Other questions to ask• How do the results compare to similar
buildings?• What were the major assumptions?• For existing buildings…
How close does the model match utility data? Was actual weather data used or “typical” year?
Energy Modeling for Owners
Building Energy Model Basics
Reasons to do a Building Energy Model
Selecting an Energy Modeler
Information Exchange with the Modeler
Economic Analysis and Decision Making
Economic Analysis Who will do the economic analysis? What is the acceptance criteria?
• Simple payback Consider how long until the component will be
replaced• ROI• Life cycle cost – best for long-term
economics Use appropriate life cycle period for each
component
Economic Analysis Factors to consider
• Energy cost savings (from the energy model)• Cost to implement the upgrade• Maintenance cost savings• Reduced investment due to smaller
heating/cooling equipment• Inflation• Discount Rate• Tax benefits• Utility rebates / incentives• Years to component replacement
Economic Analysis Uncertainty of implementation cost
Get quotes Be careful using a crude estimate in the
analysis Consider determining the present value of
future savings – “break-even” cost Easy to compare to an uncertain
implementation cost when bids come in If the bid is less than the break-even
cost, then the upgrade is beneficial
Economic Analysis Consider checking sensitivity
Energy cost savings estimates and implementation costs are uncertain
Check a range of values
Energy Modeling for Owners
Building Energy Model Basics
Reasons to Do a Building Energy Model
Selecting an Energy Modeler
Information Exchange with the Modeler
Economic Analysis and Decision Making