The Northwest Energy Efficiency Alliance (NEEA) contracted with Larson Energy Research and Cascade Engineering Services, Inc. to conduct a laboratory assessment of the Rheem 120-volt heat pump water heaters (HPWH), a new class of HPWH coming to market that can operate on a 15-Amp, 120-Volt circuit. This report seeks to answer questions about their performance capabilities using results from laboratory testing. It is intended to help identify the most appropriate installation locations for these “plug-in” water heaters.
Lab testing used two integrated style models: dedicated-circuit, with a maximum current of 12A, and shared-circuit, with a maximum current under 7.5A. Both models have a 50-gallon storage capacity, and neither has electric resistance elements. Each was tested using 125° F and 140° F water storage setpoints, with a mixing valve set to 120° F; and tests were performed in three ambient conditions: 50° F, 68° F, and 95° F. The complete results inform a heat pump water heater selection guide to help installers and consumers arrive at the best option given their unique installation.