Modeling Heat Pump Water Heater (HPWH) for Comfort Cooling

An air‑source heat pump water heater (“HPWH”) (or the “emerging technology”) uses a reversed “Carnot” refrigeration cycle to heat potable water stored in a tank and may incorporate an electric resistance element as a supplemental heat source. During operation, the unit expels cool air, which can provide incidental space cooling and potentially reduce the load on the primary space conditioning system. This secondary cooling effect may improve overall energy efficiency and lower the HPWH’s carbon footprint, enhancing its competitiveness as electricity prices rise.This project proposes to model the cooling performance of HPWHs and assess their potential to deliver associated cooling energy savings. It aligns with the “Water Heating—Unitary and Single-Family Systems” category and addresses key market barriers, including the cost-effectiveness of HPWH fuel substitution, which can be negatively affected by high equipment and installation costs, existing electric and gas tariff structures, customer concerns about rising electricity prices, and grid integration challenges.The expected outcome of this work is to inform a subsequent laboratory or field study, which could support either revisions to existing residential measures or the development of new ones.