Heat pump > Tankless > Tank
Why heat pump water heaters dominate the rebate stack
The IRA picks winners. Heat pump water heaters (HPWH) are the clear winner: federal stack of $2,000 (25C) + $1,750 (HEAR) + most utilities offer $300-$700 rebates. Tank and tankless gas water heaters get smaller credits ($600 max) and fewer utility rebates.
Federal stack — heat pump water heater
- 25C credit: $2,000 max (30% of cost). ENERGY STAR Most Efficient required.
- HEAR rebate: $1,750 (≤150% AMI). Point-of-sale in most states.
- HOMES rebate: contributes to the modeled-savings tier; not standalone
Federal stack — tankless gas water heater
- 25C credit: $600 max. Must be ENERGY STAR.
- No HEAR (electrification only)
- Utility rebates: $50-$300 typical
Federal stack — tank water heater (electric or gas)
- 25C credit: $600 max for high-efficiency. Most standard tanks don't qualify.
- Almost no utility rebates for standard tanks
Heat pump water heater 101
HPWHs use a small refrigeration cycle to extract heat from ambient air and transfer it to water. They use 60-70% less energy than electric resistance tanks. Drawbacks: needs ~700 cubic feet of conditioned space (won't fit in a tiny mechanical closet); cools and dehumidifies the surrounding room (great in summer, less great in unconditioned basement in winter); makes some noise (~50 dB).
Common installation gotchas
- Existing 30-amp circuit may need to be upgraded for HPWH (check nameplate amperage)
- Adding a condensate drain line is required (HPWHs produce condensate like an AC)
- If water heater is in a closet, the closet typically needs vents or louvers added
- 50-65 gallon tank is standard for HPWH (vs 40-50 for electric resistance) — make sure space accommodates