How Heat Pump Water Heaters Work
HPWHs use electricity to move heat from one place to another instead of generating heat directly, like a refrigerator running in reverse. While a refrigerator pulls heat from its interior and exhausts that heat into the surrounding room, a heat pump water heater pulls heat from the surrounding air and transfers it into the tank to heat the water.
There are different types of heat pump water heaters:
- Integrated units: also called one-piece, drop-ins, or stand-alones. Some of these heat pump water heaters can be fitted with intake and/or exhaust ducts, according the needs of a particular installation location.
- Add-on units: are attached to an existing storage water heater
- Split systems: have a heat pump compressor that is separate from the tank to provide flexibility in installation locations.
Only integrated units meet the performance specifications required for ENERGY STAR qualification at this time. These are the only units that currently qualify for BPA's energy efficiency reimbursement, in addition to other requirements.