Heat Pump Water Heating

graphic of water heater

Impact: High

Gas water heaters are the second largest users of natural gas in homes after gas furnaces.


Heat pump water heaters use electricity to extract heat from the air and compresses it to transfer to the water through condenser coils. The heat pump system works like your refrigerator in reverse and is highly efficient.


  • Energy efficiency
    By transferring heat rather than generating it, heat pumps are more energy efficient compared to gas and electric resistance water heaters.
  • Improved indoor air quality
    Gas water heaters burn natural gas, emitting carbon monoxide and nitrogen dioxide during the combustion process. Replacing gas water heaters improves air quality in your home and reduces safety risk.
  • Cost
    With rebates, switching to a heat pump water heater is about equivalent to a gas water heater replacement.

Depending on the age of your current water heater, it is a good idea to plan for a heat pump water heater when the gas water heater breaks down. The typical lifespan for water heaters is around 10-15 years. Installing a heat pump water heater may require installation of new outlets that can be hard to complete on short notice. Planning for a heat pump water heater ahead of time will enable you to effectively switch to a heat pump water heater when the gas water heater breaks down. If your gas water heater is old enough, it might make sense to make the switch now instead of waiting for it to break down.

Preparation Considerations

Increased electric load:

  • Most heat pump water heaters require about 30 Amp to operate and a 220/240V circuit breaker. This may require installation of a new 240V outlet and may trigger an electric panel upgrade. Learn more about the Watt Diet to see how you might be able to avoid a panel upgrade while switching to electric, see Electric Panel and Watt Diet.
  • Retrofit ready models that use 120V, 15 Amp circuits are becoming increasingly available and may be a viable option to avoid electric panel upgrades or installing a new 240V outlet.  

Space Requirements:

  • Heat pump water heaters are typically installed in a garage, basement, or attic as they are best suited for an unconditioned space.
  • The system takes up slightly more space than a conventional gas water heater – 700 cubic feet or more with 6" clearance above and around is usually recommended for better airflow.
  • The system produces water that needs a small water pipe routed outside, or to a drain or a sink. 


  • The system creates about 50 decibels of fan and electrical motor noise, similar to a dryer.

Other options

  • Tankless alternatives are available for homes that do not have space for a water tank. Many of the options currently still use electric resistance but some heat pump hybrid versions are appearing in the market.