Residential Weatherization Calculator

1. Deriving Realistic Savings Estimates for the “Uninsulated” House Residential Weatherization Calculator

2. What Is The Issue? • All prior evaluations have measured “average” savings for the mix of ResWX measures installed in programs • The “average” house already was partially weatherized • Savings from the installation of individual measures has been estimated using engineering simulation models “calibrated” to an average package of measures.

3. Simulation Model Assumptions • Historically, all “cost-effectiveness” analysis has held “consumer behavior” (i.e., thermostat set-point) constant across all thermal integrity levels • 65 F weighted average set point • 70 F – 8 hours/day • 62 F – 16 hours/day • This assumes that consumers in very poorly insulated homes would prefer to be just as comfortable as those in well insulated homes

4. Prior Modeling Assumption Justification • Experience in the Hood River Conservation Project showed that once houses were “super-weatherized” consumers: • Stopped burning as much wood • Set up the thermostat on their electric heat • BPA ResWX evaluations have shown that “net” savings increased over time as comparison group use “rebounded” after the rate increases of the early 1980’s dissipated • If they can afford it, people will keep their homes warmer

5. Re-Calibration Process • Compared Simulated Space Heating Use with Sub-metered Space Heating Use • Sample – 617 SGC Homes w/Zonal Heat (Sample contains only sub-metered homes with space heating use of at least 1.0 kWh/sq/ft/yr.) • Some homes had wood heat & used it • Average Use = 3.48 kWh/sq.ft./yr • Average Size = 1596 sq.ft. • Weather – Portland & Seattle

6. Approach • Fit Regression Line Through Sub-metered Use vs. Building Heat Loss Rate • Adjusted SUNDAY Simulation Set-point Temperature, Thermal Mass and Internal Gains to Match “Heating Slope” of SGC Data Set

7. SGC Sub-metered Use vs. Building Heat Loss Rate

8. Simulations Results Compared to SGC Submetered Data – Total UA

9. Simulations Results Compared to SGC Submetered Data – UA/Sq.Ft.

10. Sample Results Zone 11350 sq.ft. Home w/Zonal Heat

11. Recommendation • Use Standard Modeling Input Assumptions for purposes of determining “cost-effectiveness” • Use “Modified” Modeling Input Assumptions for purposes of estimating “realizable” savings from weatherization • Thermostat set-point decreases by 0.1 F for every 15 Btu-F Increase in Heat Loss Rate for non-basement house and 0.15 F for homes with basements • 3000 Btu/hr Internal Gains (Inefficient Appliances)