SA-12-C004 -- Measured Impact on Space Conditioning Energy Use in a Residence Due to Operating a Heat Pump Water Heater Inside the Conditioned Space

The impact on space conditioning energy use due to operating a heat pump water heater (HPWH) inside the conditioned space is analyzed basedon 2010-2011 data from a research house with simulated occupancy and hot water use controls. The 2700 ft2 ( 251 m²) house is located inOak Ridge, TN (mixed-humid climate) and is equipped with a 50 gallon (189 L) HPWH that provided approximately 55 gallons/d (208L/d) of hot water at 120°F (48.9°C) to the house during the test period. The HPWH has been operated every other week from December2010 through November 2011 in two modes; a heat pump only mode, and a standard mode that utilizes 15355 Btu/h (4500 W) resistanceheating elements. The energy consumption of the air-source heat pump (ASHP) that provides space conditioning for the house is compared for thetwo HPWH operating modes with weather effects taken into account. Impacts during the heating and cooling seasons are compared.