Prescriptive Duct Sealing UES Measure Proposal

1. Prescriptive Duct SealingUES Measure Proposal Regional Technical Forum Subcommittee July 8, 2013

2. Overview • BPA is proposing a new “Prescriptive Duct Sealing” measure • This measure does not replace the “PTCS Duct Sealing” measures. • Proposed UES Measure Category: Planning • The Guidelines require: • UES Estimation: Baseline and Efficient-case can be estimated • Research Plan to bring measure to Provisional or Proven category • Goal for the Subcommittee: • Review the measure proposal in detail for compliance with the guidelines. Provide feedback to BPA and SBW for improvements. • Three primary components for review according to guidelines: • Measure Specifications • UES estimation method and input assumptions • Research Plan (this is being proposed as a provisional measure) • Consensus on the subcommittee’s recommendation to the RTF regarding the measure (Adoption? Edits? Options to consider?)

3. Measure Specification Summary • Applies to existing single family or existing manufactured homes • Measures for four heating systems • eFAF w/CAC • eFAF w/o CAC • Heat Pump • Average (any of the three above) • Site Qualification • 30% or more of supply ducts in accessible unconditioned space • Exception for high pressure leaks, new duct systems; clarification on conditioned space; clarification on accessibility of ducts; no previous PTCS sealing • Duct Repair and Support • Sealing Requirements • Accessible portions must be sealed • Description of sealing that must take place • Replacement of removed insulation • CO alarm required in houses with Combustion Appliance Note: This is a summary. See the Specification for more details.

4. UES Estimation Method Summary • Use the same methodology (and savings) as the existing PTCS UES measures • SEEM Simulation • Constant Parameters • Fully Weatherized House • 12% of homes have 0 savings • Primary Parameters • Supply Duct Leakage (% of Air Handler Flow) • Baseline SF: 15% MH: ~20% • Efficient-Case SF: 5% MH: ~6% • These primary parameters will be updated once data collection as per research plan is complete. Note: This is a summary. See the Summary Sheet for more details.

5. Research Plan Summary • Objective: Reliably estimate duct leakage fraction for the baseline and efficient case for regional eligible population of SF and manufacture homes. • Sample Design and Data Collection • Baseline • For 80/20, use the RBSA leakage test results on the 44 applicable homes. • For 90/10, perform duct leakage testing on remaining eligible 206 homes in RBSA and study variance in leakage results. • Efficient-Case • Select a random sample from prescriptive measure deliveries. • For 80/20: A sample size of 16 SF and 15 manufactured homes • For 90/10: A sample size of approximately 116 SF and 116 manufactured homes • Budget (assumes $500/house for duct testing) • For 90/10: $341,000 • For 80/20: $15,500 Note: This is a summary. See the Research Plan for more details.

6. Research Plan Discussion • Will the RBSA sample represent homes that come through the program? • Current Assumption: Yes • If not, then we may need to do pre-tests, which would likely bias the post leakage measurements. • Will 20% precision at 80% confidence on the baseline and efficient-case leakage rates be good enough, or should the plan “require” 90/10? • The available baseline data, which satisfies 80/20, shows 28% precision at the 90% confidence level. • This means the baseline leakage is anywhere from to 7.1% to 12.5% (at 90% confidence). • We might expect the efficient-case leakage to be 5%. • That gives us a very wide range of “delta” leakage: 2.1% to 7.5%! • Note that this hasn’t taken into account uncertainty in the efficient-case, yet, which will compound the problem.