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 heater systems typically have higher initial costs than conventional storage water heaters. However, they have lower operating costs, which can offset higher purchase and installation costs.
