All-Electric or Solar Water Heating
Water heating is all-electric (heat pump preferred) or solar.
Spec
Applies uniformly from Gold upward.
Scope
The primary domestic hot-water heater serving the dwelling. Recirculation loops and point-of-use boosters are downstream of this and not constrained by this requirement.
Requirements
- 01.
The primary water heater must be either: (a) a heat-pump water heater (HPWH), (b) an electric-resistance water heater, or (c) a solar-thermal system with an electric backup.
- 02.
HPWH is strongly preferred — it delivers the same hot water with ~70% less electricity than resistance.
- 03.
For Platinum, electric-resistance alone is not sufficient (HPWH or solar required).
Documentation
Evidence the inspector / Institute will need.
- 01.
Manufacturer spec sheet showing UEF (Uniform Energy Factor) ≥ 2.0 for HPWH or ≥ 0.92 for resistance.
- 02.
Photo of the installed unit with model number visible.
- 03.
For HPWH: documentation that the installation location meets the minimum ambient air-volume requirement (typically 1000 cu ft, or ducted intake/exhaust).
Guidance
Heat-pump water heaters in practice
HPWHs need ambient heat to extract — they actually cool the room they're in by ~5°F and dehumidify it. Ideal locations: garage in warm climates, basement, dedicated utility room. Avoid bedrooms (compressor noise is real) and very small closets without ducting. Hybrid units allow electric-resistance fallback for high-demand periods.
Resources
- ENERGY STAR HPWH →
List of qualifying models, plus the federal tax credit guide.
- Rewiring America HPWH guide →
Plain-language buyer guide with sizing and selection tips.
Note
Federal Inflation Reduction Act offers a 30% tax credit (up to $2,000) for HPWHs through 2032, plus utility rebates of $500-$1,500 in many areas. Stack these for under $1,000 net installed cost on many models.