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Proposed Revision to Energy Star New Homes Deemed Savings. September 19, 2008. Background – Why Update Savings. Current Savings Estimate Do Not Reflect Current Standards and Market Conditions Heat Pump & CAC Current Baseline = HSPF 7.0/SEER 11
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Proposed Revision to Energy Star New Homes Deemed Savings September 19, 2008
Background – Why Update Savings • Current Savings Estimate Do Not Reflect Current Standards and Market Conditions • Heat Pump & CAC • Current Baseline = HSPF 7.0/SEER 11 • Revised Baseline = HSPF 7.7/SEER 13 (New federal standard) • Energy Star minimum = HSPF 8 (original) vs. HSPF 8.5 (new) • Dishwasher • Current Baseline = EF-52 • Revised Baseline = EF-60 (AHAM 2004 sales weighted average EF) • Energy Star minimum = EF-58 (original) vs. EF-65 (new Energy Star spec) • Windows • Current Baseline = Class 40 • Revised Baseline = Class 35 (Based
Background – Why Update Savings • Energy Star Lighting • Current estimates do not reflect “new construction” lighting power densities • Alternative Energy Star lighting “packages” not integrated into savings estimates • Thermal shell baseline not consistent with revised energy codes • Heat Pump “Control Mix” Do Not Reflect Results of Regional Heat Pump Evaluation • Current assumptions too pessimistic for “baseline” • PTCS assumptions slightly pessimistic, but probably OK
Heat Pump Control Strategies • Ideal - ARI controller from testing method • Comfort Assist - First stage ER operates below 30º • Five Plus - 5 kW first stage with the compressor, all temperatures • Low Ambient - Compressor off below 30º, ER only • Outdoor Tstat - Ideal controller with ER lockout above 40º
Control Weightings • RTF– 2003 calculation, used current EStar calculator and “deemed savings” values • ETO—2005 weighting for Energy Trust of Oregon Resource assessment • Estar Homes—2005 weighting used in EStar savings estimates for Alliance • HP2005—Results of Heat Pump study
Alternative Control Weightings Impact on Heat Pump System Efficiency & Performance
Control System Assumption Impact on System Efficiency – Current Assumptions
Recommended Calculator Revisions • Since Heat Pump now require Outdoor Tstat and set-up for ODT PTCS control assumptions should be revised to include “Ideal” controller and “Outdoor T” controller • Base Case control assumptions should be adjusted to more closely reflect field observations
Revised Control System Assumption Impact on System Efficiency
New Home Lighting Power Densities Are Higher Than Currently Assumed Current LPD Assumption Source: NEEA New Construction Survey
New Homes Have Double the Currently Assumed Number of “Sockets” Current Assumption Source:NEEA New Construction Survey
CALMAC Results = No Correlation Between House Size & Average Hrs of Lighting Use Source: CFL Metering Study – Final Report. Prepared for Pacific Gas & Electric Company, San Diego Gas & Electric Company and Southern California Edison by KEMA, Inc. February 25, 2005
Proposed Revised Energy Star Lighting Savings Assumptions • Current Assumptions – 15 CFLs installed per home operating 2.67 hrs/day • Proposed Revised Assumptions (and specifications) • Energy Star Lighting Package 1 (minimum) = 30 CFLs • Energy Star Lighting Package 2 = 45 CFLs* • Energy Star Lighting Package 3 = 54 CFLs** • All packages assumed to operate 2.0 hrs/day *or maximum hardwired LPD of 0.8 Watts/sq ft ** or maximum hardwired LPD of 0.6 Watts/sq ft
Proposed Revised Energy Star Deemed Savings for Lighting Packages
Proposed Revised Baseline Thermal Shell Assumptions – Alternative 1 (code)
Proposed Revised Baseline Thermal Shell Assumptions – Alternative 2 (Current Practice)
Estimated Energy Star Home Deemed Savings Using Alternative Thermal Shell Assumptions
Proposed Thermal Shell Revisions • Alternative 1 • Uses code as baseline, avoids paying incentives to “meet” code • Does not reflect actual building practice • Alternative 2 • Reflects actual incremental improvement in thermal shell, hence savings • Does not appear to reflect current market share of Energy Star windows
Current and Revised Energy Star Homes Deemed Savings - Zonal
Current and Revised Energy Star Homes Deemed Savings – Heat Pump* *Do not reflect revised control assumptions
Current and Revised Energy Star Homes Deemed Savings – Gas Furnace w/o CAC
Current and Revised Energy Star Homes Deemed Savings – Gas Furnace w/ CAC