Now that it’s summer, do your customers dread going from their comfortable air conditioned houses into their hot garages at the end of the day? What if you could provide homeowners with an “air conditioner” in their garage and lower their utility bills at the same time? What if it were also good for the environment? Would you do it? Believe it or not, it’s possible.

A heat pump water heater will help cool the air in a garage, or wherever it’s located, while costing less to operate than either a gas or a conventional electric water heater. The lower operating costs will quickly make up for higher purchase costs. When compared to a conventional electric water heater, the payback period for a ten-year warranty heat pump water heater is about 1 1/2 years. The payback period compared to a gas water heater is a little under 5 years.

Heat pump water heaters are more commonly know as hybrid water heaters because they can heat water using either a small self-contained heat pump that sits on top of the tank or a conventional electric water-heater element. A number of manufacturers, including GE and Rheem, produce hybrid water heaters.

How it works

A hybrid heater has the additional benefit of cooling the surrounding air when it runs a compressor to heat the fluid, water, inside it – sort of like a refrigerator but in reverse. When a refrigerator cools what’s inside, it “exhausts” heat to the surrounding air from its coils in back or below. A hybrid water heater exhausts cold. Your air conditioner or heat pump uses exactly the same principles as the hybrid water heater.

There are considerations about heat pump water heaters that you need to take into account. First hybrid heaters require air circulation to operate properly. This is no problem if the water heater is open to a garage. However if the unit is installed in a closet, venting will be needed. But outside air is not required. Additionally, when a hybrid unit is operating in heat pump mode it is slightly louder than a refrigerator. Again this is no problem when installed in a garage. But the sound is noticeable in a quiet house. Finally, the cool air that the unit produces is great in a garage in the summer (although I don’t know how much it will lower the temperature of the average garage), but could be a problem in a house in the winter, because it might cause a cold spot.

Real life experience

Tucson Artisan Builders installed a GE Geo Spring 50-gallon heater in a closet located off a vestibule between a guest bedroom, back door, and the great room. After almost four years of operation, our customer is happy with the unit and its low utility costs. Localized cooling can be felt but has not been a problem, nor is noise, but it is evident when the unit is operating.

Dante Archangeli is the owner of Tucson Artisan Builders LLC, has been a Southern Arizona Home Builders Association member since 2000, and a green builder for longer than that. He also blogs about sustainability at GoodNewsForNature.com and terrain.org/author/darchangeli/.