1. SEEM 94 Calibration to Single Family RBSA Data Regional Technical Forum January 23, 2013 Analysis Performed ByAdam Hadley Cursory Reviews By Tom Eckman, Ben Larson, David Baylon, Nick O’Neil, Josh Rushton Presentation ByAdam Hadley

2. Introduction SEEM is used to estimate energy savings for most space- heating-effected residential UES measures Goal – Ensure SEEM’s results are grounded in measured space heating energy use. Method 1.Run SEEM using characteristics data from billing analyses and/or metering reports to define inputs. 2.Compare SEEM’s heating energy use outputs to the reports’ findings. 3.Modify unknown characteristics data (usually T-stat setting) until a reasonable match is found. 4.Standardize the “calibration inputs” (from step 3) for use in RTF measure analyses. Introduction - 2

3. RTF Guidelines 3.3.3.2 Model Calibration In most cases, calibrated engineering procedures will involve at least one stage of modeling in which baseline and efficient case energy consumption are estimated for the measure-affected end use. For example, the heating load for single-family homes is estimated as part of the derivation of UES for ductless heat pump conversion. A simulation model is used to derive the heating end use for typical homes in different climate zones. Ideally, the model would be calibrated to measured heating end use for a sample of homes. If end use data are not available, the model should at least be calibrated to metered total use for the sample. Calibration should also be performed for samples that have adopted the measure, i.e., the efficient case. For measures that affect new buildings the calibration may be limited to the efficient case or to comparable buildings of recent vintage. Introduction - 3

4. History 11/9/2009 – SEEM92 Single Family Calibration Approved 70°F/64°F for Gas FAF and HP’s 66°F for Electric FAF and Zonal 12/13/2011 – RTF adopted SEEM 94 Infiltration Calculation now physics-based (previously assumed at a steady rate) – SEEM94 Manufactured Home Calibration Approved 69.4°F/61.9°F for all heating system types 9/18/2012 – SEEM94 Multi-Family Calibration Approved 68°F for walk-up and corridor buildings 66°F for townhouses Introduction - 4

5. Data Sources SF Data Sources used in previous calibration: Data Source used in this calibration: – Underlying database** for the Single Family Residential Building Stock Assessment (2012) RBSA study’s database offers recent billing analyses results and detailed house characteristics on 1404 houses in the Region. This allows well-defined SEEM runs for each individual house. ReportDateTypen* Single-Family Residential New Construction Characteristics and Practices Study (RLW for NEEA) 2007Billing Analysis114 Analysis of Heat Pump Installation Practices and Performance (Ecotope for NEEA) 2005Billing Analysis381 Super Good Cents Metered Data~1994Billing Analysis740 Method - 5 *Sample size used in the calibration exercise (study sample size may have been larger). ** Using a pre-release version of the database for this analysis.

6. Key Model Input Parameters RBSA Data Availability UAAvailable for each house. WeatherZip code (available for each house) linked to nearest TMY3 weather station. Gas Heating EfficiencyAvailable for some houses; used average for remaining houses. HP Operation & EfficiencyNot readily available. Used ARI control & 7.9 HSPF. Duct System Leakage and Surface Area Available for some houses; used average for remaining houses with ducts. Duct System Insulation and Location Available for each house. InfiltrationAvailable for some houses; used a floor area-scaled average (by foundation type) for remaining houses Mechanical VentilationNot available. Assumed 2 hours /day at 50 cfm. Non-Lighting Internal GainsNot available. See next slide for details. Lighting Internal GainsLPD available for each house; assumed 1.5 hours/day. T-stat SettingAvailable based on interviews, but used this as the “calibration knob”. Method - 6

7. Non-Lighting Internal Gains Method - 7 *Hendron, Robert. "Building America Research Benchmark Definition, Updated December 20, 2007." NREL/USDOE EERE. January 2008. NREL/TP-550-42662

8. Some Houses Unable (or unwilling) to Run with SEEM IssueCount More than one foundation type331 25% > Ceiling Area to Floor Area > 200%, or Missing Ceiling U-value36 Footprint Area to Floor Area < 20%36 30% > Wall Area to Floor Area > 200%, or Missing Wall U-value24 Missing Floor U-value for Crawlspace Foundation5 Window Area = 03 Window u-value = 03 Resulting House Count: 1011 – These issues overlap on some houses, so the sum of the counts cannot be subtracted from 1404 to get 1011. Method - 8

9. Data Filters VariableFilter Value(s) NotesCount (filtered out) SEEM RunValidSEEM run must be valid (> 0 kWh/yr).4 Billing Energy Use> 1,500 kWh/yr Intends to screen out partially used or unused houses 38 eRsq and gRsq= 0 or ≥0.45 Screens out houses with poor billing analysis results (0.45 per David Baylon) 398 Non-natural-gas & non-electric Fuel Use 0Screens out houses with wood, oil, propane, etc. consumption because billing analysis not performed. 352 Primary Heating System eZonal, eFAF, gFAF, HP Removes gas boilers, wood stoves, etc.216 Secondary Heating System Fuel Electric or Gas Removes wood stoves, propane heaters, etc.274 Gas Billing converted to kWh/year using reported AFUE Resulting House Count: 289 (The counts for each item overlap here, too) Method - 9

10. Results Results - 10

11. T-Stat Setting “Calibrated” to: Heating System Type Heating High °F (day) Heating Low °F (night) Electric Zonal 64 Electric FAF Gas FAF68.663.9 Heat Pump69.665.4 Results - 11 Electric Zonal and FAF based on results Gas FAF and Heat Pump based on average from RBSA (n=1011 subset).

12. Results - 12

13. Results - 13

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17. Alternative Method This is how the RTF has performed SEEM calibrations in the past – Results shown here for comparison; not intended to be used as part of calibration – Modeling each house is considered a better approach Compare Averages: RBSA average billing data vs. SEEM runs with Average RBSA characteristics – Using only RBSA data from the report to define SEEM run characteristics for the 3 prototypes Exception: Used database to determine how many R0 duct insulation cases had ducts inside – Note: Used T-stat setting per RBSA report 68.7°F with 65% of homes using a setback to 62.2°F Results… Alternative Method - 17

18. Alternative Method - 18

19. Alternative Method - 19

20. What are the Takeaways? Key SEEM inputs RTF carries forward for future Single Family space heating modeling: – Tstat settings (see table) – Internal Gains Method Non-lighting: Use modified equation with RBSA average # of people/house for each prototype Lighting: Use RBSA average LPD & 1.5 hours/day – Baseline Ventilation 2 hours/day at 50 cfm – Baseline Infiltration Conclusion - 20 Heating System Type Heating High °F (day) Heating Low °F (night) Electric Zonal 64 Electric FAF Gas FAF68.663.9 Heat Pump69.665.4

21. Remaining Issues Wood/Other Heat – By ignoring the significant fraction of wood/other heated homes in this analysis, future RTF analyses will likely overstate the electric space heat savings. From a cost-effectiveness perspective, this may be ok if we consider the value of wood/other fuels similar to the value of electricity. From an electric savings perspective, it’s important to remember some fraction of the stated electric savings will actually be wood/other savings, not actual electric savings. Unused Homes – By ignoring unused homes in this analysis, we have a similar issue as with wood/other heat (except there won't be wood/other savings in these cases). Discussion - 21

22. Some Options 1.Leave as is; note caveats regarding stated savings 2.Determine a “grid savings” and a “TRC savings” for each measure – Grid Savings Savings would account for wood/other and unused houses. – This will take more work & discussion. Used to report electric savings. – “TRC Savings” Savings don’t include the effects of wood/other heat. – Savings would be based on the calibration presented today. Used to report TRC – Value of electricity used as a proxy for value of wood/other heat Discussion - 22

23. Decision Approve SEEM94 calibration for use in estimating space heating energy savings in single family homes. Decision - 23