PTCS Ducts Inside Single Family New Construction Energy Savings and Cost Regional Technical Forum May 5,

Assumptions Cost – $350 for PTCS Duct Sealing – $650 to move ducts inside – $300 for incremental cost where duct sealing was required Savings (Method: SEEM) – 2200 ft 2 prototype – Insulation Package: Energy Star shell – Heating System Type/Efficiency: 8.5 HSPF/SEER 13 heat pump with PTCS controls – Duct Leakage Unsealed (baseline “a”) – 12% Supply; 10% Return Energy Star Sealing (baseline “b”) - 6% Supply; 3% Return Ducts Inside (upgrade) – 1% Supply; 1% Return (achieved by following PTCS Ducts Inside Specs) – Measure life = 25 years – Crawlspace weighting – 90%; Slab on grade weighting – 10% (Reminder: This measure only applies to houses with < 50% basement or conditioned crawlspace, by overall foundation area) – PNW Cooling Weightings 2

Results (Recommendation) 3

Assumption: Heat Pump System Efficiency Q: Why not assume 7.7 HSPF w/o PTCS Controls? A: Savings are similar: 4 (Also, using one assumption simplifies program design, and by assuming 8.5 HSPF, there won’t be double-counting of savings if/when a heat pump efficiency upgrade occurs.)

Assumption: Heating System Type Q: What about the savings where a house has an electric FAF? A: Recommend savings calculation assumes a heat pump is installed, for the following reasons: - Add conservatism to the modeled savings calculation (which doesn’t account for wood heat) - Program simplicity (not many new single family homes heated with electric FAF’s) 5

Assumption: Slab/Crawlspace Mix Q: What justifies melding the slab savings at 10% and crawlspace savings at 90%? A: They have similar savings (and it’s simpler for programs to have one measure): 6

Assumption: Cooling Weightings Q: Why use PNW mix instead of actual cooling zones? A: Cooling savings are insignificant, so introduced error is minor. Simplifies program design & implementation 7 Note: Assumes crawlspace and 8.5 HSPF heat pump w/PTCS Controls