A heat pump can be used to heat water, either as a stand-alone water heating system, or as a combination water heating and space conditioning system. These units are sometimes called “hybrid” systems.
Instead of generating heat directly, heat pump water heaters use electricity to move heat in the air from one place to another. Therefore, they can be more energy efficient than conventional electric resistance water heaters. To move the heat, they work like a refrigerator in reverse. While a refrigerator pulls heat from inside a box and dumps it into the surrounding room, a stand-alone air-source heat pump water heater pulls heat from the surrounding air, concentrates it and dumps it—at a higher temperature—into a tank to heat water. 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. You can also retrofit a heat pump to work with an existing conventional storage water heater, though this is not typical.
Heat pump water heaters typically will not operate efficiently in a cold space. If the surrounding space is too cold (<55 degrees Fahrenheit), they will operate in electric resistance heat mode, like a conventional storage hot water heater. They also tend to cool the spaces in which they are located. Some people choose to install them in a space with excess heat, such as a furnace room. You can also install an air-source heat pump system that combines heating, cooling, and water heating. These combination systems pull their heat from the outdoor air in the winter and from the indoor air in the summer.
Some Benefits
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Can be more efficient, and often have lower operating costs, than a storage system
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Typically have 10+ year warranties
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Dehumidify the space they are in
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No combustion or venting needed
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ENERGY STAR® rated options
Some Considerations
- Hot water heat pumps need to be indoors with certain requirements (e.g., require open room with 6' or greater ceiling)
- Depending on the model, they can be as noisy as some window air conditioners
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Energy savings will vary depending on installation location
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Need a condensate drain
Learn More
Energy.gov provides information about heat pump water heaters.
Visit the pages below to learn more about different types of Hot Water systems:
