The AO Smith Voltex is the hybrid heat pump variant of AO Smith's residential lineup — direct competitor to Rheem ProTerra. Same 10-year warranty class, but with a refrigerant-based heat pump that uses ambient air to heat water at one-third the electrical cost of a resistance electric tank.
The two Voltex models
- Voltex 50G (HPTU-50N) — 67 GPH FHD, 3.42 UEF, for 2-4 person households
- Voltex 80G (HPTU-80N) — 89 GPH FHD, 3.45 UEF, for 4-6 person households
How a heat pump water heater works
A heat pump pulls heat from the ambient air using a refrigerant cycle and transfers it to the water. Result: 3.4-3.5 units of heat energy per unit of electrical energy consumed (3.42 UEF on Voltex). Trade-off: the unit pulls heat out of the surrounding air. Exhaust is cool (~50°F) — helpful in summer, can chill the install location 5-10°F in winter.
Operating cost comparison
| Unit | Annual cost (4-person, $0.14/kWh) |
|---|---|
| AO Smith Signature 100 50G Electric (resistance) | $580-$720 |
| AO Smith Voltex 50G (heat pump mode) | $170-$240 |
| AO Smith Signature Premier 50G Gas (atmospheric) | $280-$380 |
Voltex cuts electricity vs resistance by $350-$500/year. Over 12-year tank life: $4,200-$6,000 saved.
Upfront cost and incentives
Voltex 50G MSRP: $1,649-$1,899 vs Signature 100 50G Electric at $549-$799. Upfront premium ~$1,000. But:
- Federal IRA 25C tax credit: $2,000 for heat pump water heaters
- State / utility rebates: $300-$1,200 in incentive-eligible states
Net cost after incentives often comes in below the standard electric tank, plus operating savings.
Install requirements
- 1,000+ cu ft ambient air at install location
- Condensate drain or pump (2-4 gal/day)
- 30-amp 240V dedicated circuit
- 7+ ft ceiling clearance
- Compressor noise ~49 dB — don't install adjacent to bedrooms
Operating modes
- Hybrid (default): heat pump primary; electric backup during peak demand
- Heat Pump only: maximum efficiency, slower recovery
- Electric only: resistance only; fastest recovery
- Vacation: minimum maintenance temperature
Voltex vs Rheem ProTerra
Spec-equivalent. Same 10-year warranty, same UEF class, same install requirements. Rheem ProTerra ships EcoNet WiFi standard; Voltex ships iCOMM WiFi. Choose by retailer (Lowe's = Voltex; Home Depot = ProTerra).
Bottom line
Voltex is the right pick for all-electric households on long ownership horizons. Pays back upfront premium within 2-3 years through operating savings + IRA tax credit. For 1-3 person households drop to Voltex 50G; 4+ person step up to 80G.