Heat pump water heaters use electricity to move heat from one place to another instead of generating heat directly. Therefore, they can be two to three times more energy efficient than conventional electric resistance water heaters. To move the heat, heat pumps work like a refrigerator in reverse.
While a refrigerator pulls heat from inside a box and sends it into the surrounding room, a stand-alone air-source heat pump water heater pulls heat from the surrounding air and transfers it, at a higher temperature, to heat water in a storage tank. You can purchase a stand-alone heat pump water heating system as an integrated unit with a built-in water storage tank and back-up resistance heating elements.
Heat pump water heaters require installation in locations that remain in the 40-90 degree F (4.4-32.2 degree C) range year-round and provide at least 1,000 cubit feet (28.3 cubic meters) of air space around the water heater. Air passing over the evaporator can be exhausted to the room or outdoors.
Heat pump water heaters will not operate efficiently in the cold, since they tend to cool the space they are in. Installing them in a space with excess heat, such as a furnace room, will increase their efficiency.
If you are considering a heat pump water heater, ask your contractor about your options.
MMEU offers a rebate for qulaifying Heat Pump Water Heaters
You can learn more about the many uses of heat pump technology and the tax credits and rebates available through the Inflation Reduction Act here.