Heat Pump Water Heaters: Savings Potential in Minnesota
Ben Schoenbauer, Dave Bohac, P.E., Martha Hewett
Heat pump water heaters remove heat from the surrounding air and transfer it to water. Moving heat requires less energy than generating it directly, so they can be an efficient direct replacement for traditional electric storage water heaters.1 Heat pump water heaters are becoming more common in southern states, but their savings potential in Minnesota’s heating-dominated climate is undefined. And recent laboratory studies suggest that their performance rating does not accurately reflect installed energy savings.
This white paper attempts to characterize heat pump water heaters’ capacity to reduce space heating energy use in Minnesota single-family homes with electric water heaters. Engineering calculations determined potential impacts of several different unit installation configurations. The paper also reviews existing field studies on residential water usage and heat pump water heater performance and applys the findings and concepts to Minnesota’s housing stock, water use patterns, and climate. CEE also created two online calculators for rebate programs and homeowners.
This project was supported in part by a grant from the Minnesota Department of Commerce, Division of Energy Resources through the Conservation Applied Research and Development (CARD) program, with co-funding by CEE in support of its nonprofit mission to advance research, knowledge dissemination, and program design in the field of energy efficiency.
Photo courtesy of DOE/NREL.