Ranch near Ovando, Montana

Heat Pump Water Heaters — How They Work

Heat pump water heaters, also known as hybrid water heaters, operate much differently than traditional electric resistant storage tanks. As the name implies, these units utilize a heat pump to heat your domestic hot water. Heat pumps are more efficient because they move heat instead of making heat. In this case, the heat pump moves heat from the ambient air around the water heater and moves it into the water inside the tank.

How efficient are these new water heaters? In our climate, these heaters can have an energy factor of 2.7, which means for every dollar of electricity you put into them, you get $2.70 in hot water. For comparison, the best 50-Gallon Electric resistant hot water heater has an energy factor of 0.95, so for every dollar of electricity you put into the tank, you get 95 cents worth of hot water.

Qualifying Heat Pump Water Heater Models (PDF)

Things to Consider

  • Hybrid water heaters make noise. All hybrid hot water heaters carry a decibel rating. Units are about as loud as a good dishwasher, not completely silent, but not noticeable if they are not in the room with you.
  • Hybrid water heaters require airflow. Because these units harvest heat from the ambient air, they have minimum requirements specified by the manufacturer for what volume of air they need access to. If your current water heater is located in a closet, additional venting is required.
  • Hybrid water heaters are taller than traditional electric storage tanks. If your current unit is installed in a crawlspace, relocating to a new spot may be required.
  • Hybrid water heaters exhaust cool air. Because these units pull heat out of the air to make hot water, what is left is cool air which is put back into the same room. When running in heat pump mode, these water heater can cool the surrounding space by several degrees. Ducting kits are available to exhaust the cool air into a crawlspace or outside the home.