Code Readiness Multifamily Central Heat Pump Water Heater Research: Data Brief on Preliminary Findings from Return to Primary Testing

The Code Readiness research team is conducting field demonstrations on large central heat pump water heater (CHPWH) systems installed in multifamily buildings located in California. The intent of this research is to better understand energy performance of CHPWH systems configured as single-pass and return to swing tank as compared to the same system configured as return to primary storage tank(s). The research team completed testing of three systems. This data brief presents preliminary findings from this first round of field demonstrations. Additional field demonstrations at three more buildings with CHPWHs are being completed through March 2026. A final report will be published following the conclusion of these additional field demonstrations.