Modeled Results of Four Residential Energy Efficiency Measure Packages for Deriving Advanced Building Construction Research Targets

The Advanced Building Construction (ABC) Initiative from the U.S. Department of Energy Building Technologies Office is working to accelerate industrialized construction innovations for decarbonizing building. To inform performance and cost targets for research under the ABC Initiative, this analysis used the ResStockTM tool to evaluate the energy savings, utility bill impacts, and carbon emissions impacts of four simulated upgrade package with specific target performance levels on a large sample of residential dwelling units (approximately 550,000) representative of the U.S. housing stock. The four upgrade packages simulated were: 1) All Equipment Swap-Outs: Replacing the end-use equipment with high-efficiency electric equipment; 2) Market-Ready Envelope: Swapping out end-use equipment and upgrading the building envelope with market-ready solutions; 3) IECC Envelope: Swapping out end-use equipment and upgrading to the 2021 International Energy Conservation Code (IECC) residential prescriptive path building envelope requirements; 4) PHIUS Envelope: Swapping out end-use equipment and upgrading to the 2021 PHIUS standard building envelope requirements. The key takeaways from the analysis are: Equipment-only upgrades are estimated to lead to increased utility bills in about 10% of dwelling units (using 2019 prices). However, we only assessed one model of ducted variable-speed heat pump, which did not meet typical “cold climate” heat pump specifications. This finding will be very sensitive to the details of the heat pump efficiency level and installation configuration being modeled; Equipment-only bill increases are related to price of electricity relative to natural gas, heating oil, and propane prices. The results presented here use 2019 prices, and results will change with fluctuations in the prices of these fuels; Building envelope upgrades can significantly mitigate these bill increases, with negative bills occurring in 4%, 2%, and 1% of homes for the Market-Ready Envelope, IECC Envelope, and PHIUS Envelope packages, respectively; If implemented prior to installing the heat pumps, these envelope packages can significantly reduce required heat pump capacities and potentially avoid electrical and ductwork upgrades, saving on upfront investment costs; The net present value of utility bill savings from this analysis can be used to inform cost compression targets for the ABC Initiative; All package performance levels are expected to reduce carbon equivalent emissions in every state, regardless of future grid scenario. These findings and subsequent analysis were used to inform the forthcoming Market Guidance to Scale Zero-carbon Aligned Residential Buildings. Subsequent work will be necessary to explore additional sensitivities, including heat pump efficiency levels and cold climate performance.