Field Demonstration Findings for Minimizing Electric Resistance Use in Multifamily and Nonresidential Heat Pump Water Heater Retrofits

This study was conducted to address 1) data gaps about how large split CHPWH’s installed in existing multifamily buildings operate in an RtP configuration compared to the industry standard configuration of returning recirculation water to the systems swing tank (RtS) and 2) better understand how to optimize integrated 120-gallon HPWH’s recently installed as part of retrofit projects replacing natural gas DHW systems. The research provides primary data based evidence on successful implementation of directing the recirculation water to primary storage tanks at five multifamily sites, and an improved understanding of integrated HPWH operation in retrofit scenarios at existing nonresidential buildings. The results offer actionable insights for energy codes, standards, and programmatic initiatives, and provide a foundation for future research and development in this area.