1. Manufactured Housing Duct Sealing Pilot - Independent Evaluation Results Tom Eckhart, Howard Reichmuth, Jill Steiner Regional Technical Forum February 3, 2009

2. Program Description  Operated by UCONS, LLC from September 2005 to June 2006  Focused on sealing and repairing duct leaks in manufactured homes with electric furnaces  Provided other low-cost measures  Efficient showerheads and aerators  Temperature reset on water heater  Pipe insulation  Compact fluorescent lights  Furnace filter  Served 1,686 Snohomish customers – about 13% of manufactured homes with electric furnaces

3. Program Process Pre-Treatment Duct Pressurization Test and Visual Inspection Installation of Low-Cost Measures Post-Treatment Duct Pressurization Test B C A Level of Duct Treatment as Determined Appropriate

4. Duct Sealing Protocols  “A” sites – Ducts tested and sealed from the interior (boots, registers, end caps). Cross-over duct are inspected and if determined to still be in good condition but air leaks were identified at the crossover duct connections to the collars, the collar connections to the main duct runs, or there were air leaks in the crossover duct that were repairable. The identified air leaks were sealed with mastic, and/or repairs were made to crossover duct as required. These were referred to as “exterior treatment of crossover ducts”.  “B” sites – Ducts tested and sealed from the interior (boots, registers, end caps). Cross-over duct inspected and if found to be damaged, would be replaced. Collars sealed with mastic, new R-8 crossover duct installed and crossover duct connections sealed with mastic.  “C” sites - Ducts tested and sealed from the interior (boots, registers, end caps). Cross-over duct would be inspected and if no air leaks were found, no further work would be conducted.

5. Expected Savings MeasureNumber Installed Est per unit savings kWh/yr Percent of Homes Installed Total kWh/yr savings Low Flow showerhead 95815857.1%151,364 Aerator187660111.7%112,560 Temp reset, pipe wrap 91536054.5%329,400 CFL797833475.2%263,274 Floor insulation2702.416.1%848 Furnace Filter11677069.5%81,690 Duct inspect only “C” 581830 482,462 Duct test/seal “A” 2621044 273,580 Duct test/seal & Repair “B” 8361151 962,236 Totals1,6792,657,215

6. Data Challenges  Bi-monthly billing data  Sought 18-months pre- and post-data  Ideally, 2 years would be available for analysis  For robust sample, included some sights with less than 18- months post-data  Of the 1,686 participants, analyzable data for 572 (~34%)

7. Methodology  Compared pre- and post-treatment consumption data  Defined energy consumption as a function of average outside temperatures for pre- and post-periods  Calculated Normalized Annual Consumption (NAC) for pre- and post-periods to determine normalized average savings

8. Energy Consumption Function

9. Participant Pre- and Post-Consumption

10. Statistical Results SampleMean Savings kWh/yr Std DevN95% Lower Bound 95% Upper Bound Full Sample1,4632,6315721,2471,679 A sites1,3692,4691689931,745 B sites1,7172,7093211,4192,014 C sites6712,500831261,218 >20,000 pre2,6733,3721692,1613,186

11. Program Savings Treatment GroupAverage Savings kWh/yr Number of Sites in Program Total Savings kWh/yr A sites1,369262358,678 B sites1,7178361,435,412 C sites671581389,851 Total Program1,6792,183,941

12. Summary Results Total Number of Program Participants1,679 Mean Savings per Participant1,301 kWh/yr Total Participant Savings, kWh/yr2,183,941 kWh/yr Savings as % of Average Participant Usage 8% based on analysis sample Realization Rate of Projected Savings82%

13. Savings by Treatment Group

14. Realization Rates by Treatment Group

15. Pre- and Post- Consumption 7.3% 9.5% 3.8%  8% average savings overall  9.8% savings (> 2,600 kWh) for homes with pre-treatment consumption over 20,000 kWh

16. Savings Distribution

17. Program Cost-Effectiveness Program Cost$800,000 PV Utility Benefits$2,000,291 PV Societal Benefits$2,217,253 UCT B/C2.50 TRC B/C2.77 Levelized Cost3.7¢/kWh

18. Findings  Longer pre- and post-periods were needed to evaluate data because of bi-monthly billing cycles  More savings would have been realized with high- quality 2.0 GPM or less showerheads  Homes with greater than 20,000 kWh pre-treatment consumption yielded higher savings, but savings across all homes electric resistance central heat was significant and cost-effective

19. Questions? Comments?