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.

1. Keith Swartz
Energy Center of Wisconsin
ComEd New Construction Program
Nicor New Construction Program
Illinois ASHRAE Modeling Conference
February 14, 2012

2.  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

3.  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

4.  Limitations
 No program is perfect
 Many inputs are assumed
 Only an estimate
 Does not make decision for you

5.  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

6.  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

7.  Low-energy building
 Small
 Simple
 Energy not a concern
 Insufficient time in project schedule
 No local qualified energy modelers

8.  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

9.  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

10.  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

11.  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)

12.  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

13.  Reason for doing the energy model
 Deliverable
 Location of the building
 People
 Lights
 Plugged in equipment
 HVAC systems

14.  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)

15.  Depends on why the model was done
 The deliverable

16.  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?

17.  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

18.  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

19.  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

20.  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

21.  Consider checking sensitivity
 Energy cost savings estimates and
implementation costs are uncertain
 Check a range of values

22.  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