Heat pump water heaters work just like your refrigerator, only in reverse. Instead of removing heat from the appliance and expelling it into the room, they move heat from the room into the hot water tank. Many heat pump water heaters are “hybrid” and include conventional electric resistance heating elements to provide backup heating when hot water demand is high.

How well do they work? 

According to an NRDC study, hybrid heat pump water heaters use less than half the electricity of conventional electric water heaters. Pure heat pump water heaters are even more efficient, using less than a third the electricity. Read the full study here.

Who should use a heat pump water heater? 

Homes that use high cost fuels to heat water.  A heat pump water heater could be an excellent investment for you if you currently are using a conventional electric, oil, or propane fueled water heater. The savings from replacing a gas water heater with a heat pump water heater will be smaller, due to the currently low price of natural gas, but available incentives and rebates can offset the added upfront cost and reduce payback time.

Homes with a partially finished or unfinished basement with enough space. Heat pump water heaters are a bit taller than most traditional water heaters and need sufficient airflow to operate in heat pump mode. However, they need no exhaust connection to a chimney. They need space around them and should not be located in a small enclosed space unless ducted. They should ideally be placed in an unfinished space (like a basement) in order not to impact your heated living space, as they will lower the temperature of the surrounding space by 5 to 10 degrees F. If you locate it near your (non-heat pump) furnace, a heat pump water heater may be able to take advantage of the wasted heat generated by your furnace.

Homeowners who are concerned about climate change. Hot water production accounts for 13% of total residential energy use, the second highest category after space heating. Currently, over 40% of U.S. households heat their water with inefficient electric resistance water heaters, so making the switch to heat pump water heaters could make a big difference in residential carbon emissions. And it could save a lot of people money, too. See the NRDC’s cost analysis here.

Find out if a heat pump hot water heater is right for your home. Visit Massachusetts Clean Energy Center to request a consultation from a qualified installer. HeatSmart Alliance, an organization of volunteers encouraging heat pump adoption in Massachusetts, also has homeowner resources and technical information.