Two kinds
- Dedicated circuit: plugs into its own 120 V, 15 A outlet that nothing else uses. Usually a bit more capacity.
- Shared circuit: draws less power, so it can share a 120 V, 15 A circuit with other loads, such as the washer. Rheem’s shared-circuit ProTerra Plug-in comes in 40, 50, 65 and 80 gallons, with a mixing valve (“HydroBoost”) to stretch hot water.
Because there’s no big resistance element to fall back on, 120 V models recover more slowly than 240 V hybrids. Size one a little larger than the gas tank it replaces.
What they need
- Space and air. A heat pump water heater pulls heat from the room and blows out cooler air. Basements, garages and large utility rooms suit them; a small closet may need louvers or ducting. Check the minimum room volume in the installation manual.
- A condensate drain, because it makes water like an air conditioner.
- Some tolerance for noise, similar to a dehumidifier.
- A plumber. Swapping a water heater means water, possibly gas line capping, and code requirements such as an expansion tank. In most places it needs a licensed plumber and a permit.
Models
- Rheem ProTerra Plug-in, dedicated-circuit and shared-circuit versions.
- A.O. Smith Signature 900 120V plug-in (model HPV10-50H01DV), 50 gallons.
- A.O. Smith Voltex 120V, in 50, 66 and 80 gallons.
These sell through plumbers and home improvement stores rather than Amazon.