How Do Heat Pump Water Heaters Work?

How Do Heat Pump Water Heaters Work?

Heat pump technology is perhaps better known for heating and cooling air, but it’s also an ultra-efficient solution to water heating.

Heat pump water heaters run on electricity and work by moving heat from the surrounding air to heat water in a storage tank. A fan pulls in the ambient air and blows it across evaporator coils filled with refrigerant. The warmed refrigerant is then pumped through a compressor to increase its pressure and temperature before traveling through condenser coils to transfer heat to the water. Once cooled off, the refrigerant returns to the evaporator coils to repeat the process.

By transferring heat rather than creating it, heat pump water heaters require less energy to operate. Compared to standard electric or gas models, they deliver around three times more efficiency . The process of transferring heat from the ambient air to the water tank also dehumidifies the surrounding space.

Heat pump water heaters pull heat out of the surrounding air to heat water, rather than relying on electricity or gas to generate heat. In other words, they move energy instead of generating it. This is similar to a refrigerator, an air conditioner, and heat pumps used for space heating and cooling.As researchers at the Department of Energy put it, “Heat pumps work like a refrigerator in reverse. 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 and dumps it — at a higher temperature — into a tank to heat water.”Source: JIADELE most heat pump water heaters include a backup electric resistance heater in case the surrounding air temperature isn’t warm enough. That’s why these are also called hybrid water heaters (hybrid = both heat pump + electric resistance).Because they use surrounding air, heat pump water heaters should ideally be placed in an area of your home that remains in the 40º–90ºF (4.4º–32.2ºC) range year-round. Examples include a mechanical room, garage, crawl space, or unfinished basement.They also need 700 cubic feet (28.3 cubic meters) of air space around the water heater in order to work.