HPWH — Heat Pump Water Heater
Also known as: Heat pump water heaterhybrid water heaterelectric heat pump water heater
A heat pump water heater is a water heater that uses a heat pump (same technology as ASHP HVAC) to move heat from the surrounding air into the water tank. Roughly 3× more efficient than electric resistance water heating, and significantly more efficient than gas water heating once you account for the gas combustion losses.
Typical 2026 HPWHs use a 30A 240V circuit (some use 20A 240V), have a 50-80 gallon storage tank, and need ~700-1000 cubic feet of surrounding air space — basically a garage or utility room with airflow. They produce condensate (needs a drain) and they pull heat from their surroundings, slightly cooling the space they're in (a bonus in summer, a small negative in winter).
HPWHs used to qualify for the Section 25C federal credit alongside heat pump HVAC, but that credit ended for work placed in service after December 31, 2025. Many homes here have gas water heaters in garages — ideal locations for HPWH retrofits. We add the 240V circuit and disconnect; the HPWH itself is plumber/HVAC work. Worth asking about the 120V models before assuming a dedicated 240V circuit is needed — on a tight service that choice can remove a panel upgrade from the project.
The biggest gotcha with HPWH installs is the space + airflow requirement. We can do the electrical side anywhere, but if the existing gas water heater is in a tight closet with no air circulation, the install may need a different location or a vent kit. Worth checking before you commit to the unit.
Met this term in a quote or inspection report?
A free whole-home inspection turns jargon into a written assessment of your actual house — you keep the report either way.