Emerging Technologies: Heat Pump Water Heaters PDF

Electric resistance water heaters are common in parts of the country that don’t have gas service. Although they serve about 40% of all residences, the units account for nearly half of annual residential water heating primary energy consumption. This discrepancy reflects the low primary energy efficiency of electric resistance water heaters (about 0.27) compared to fuel-fired units (about 0.551). Heat pump water heaters (HPWHs), however, can achieve dramatic improvements in the energy efficiency by replacing purely dissipative heating with heat pumped from the surrounding air.