Rinnai REHP50
#4 in 40–50 GallonFull review
A Midea-built heater with Rinnai’s support network and one of the few listings on Amazon. Check the seller is a Rinnai-authorized dealer before buying.
Amazon $1,799 Lowe's $1,799$1,799
The Rinnai REHP50 is the better heat pump water heater overall, rated 3.6 to 3.4. The Rinnai REHP50 leads on hot water. The A.O. Smith Voltex MAX 50 Gal wins on noise. The Rinnai REHP50 costs $430 less ($1,799 vs $2,229).
A.O. Smith Voltex MAX 50 Gal
#11 in 40–50 GallonFull review
A solid 240 V heater with leak protection included, sold at Lowe’s as the Signature 900 line.
Lowe's $2,229$2,229
Prices were last checked October 21, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Rinnai REHP50 for hot water (73 gallons in the first hour vs 65 gallons in the first hour).
- Choose the A.O. Smith Voltex MAX 50 Gal for noise (45 dB(A) vs 49 dB(A)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 40–50 gallon heat pump water heater; a clear win is highlighted. How we rank explains each one.
| Factor weight | Rinnai REHP50 | A.O. Smith Voltex MAX 50 Gal |
|---|---|---|
| Overall rating | 3.6/5 | 3.4/5 |
| Efficiency 35% | 54 3.75 UEF | 49 3.68 UEF |
| Hot water 20% | 92 73 gallons in the first hour | 60 65 gallons in the first hour |
| Warranty 20% | 75 10-year tank, 10-year parts, 1-year labor | 75 10-year tank, 10-year parts, 1-year labor |
| Cold rooms 15% | 30 heat pump runs down to 37.4 °F room air | 32 heat pump runs down to 37 °F room air |
| Noise 10% | 44 49 dB(A) | 69 45 dB(A) |
Specifications
| Rinnai REHP50 | A.O. Smith Voltex MAX 50 Gal | |
|---|---|---|
| Ratings (ENERGY STAR) | ||
| Size (nominal) | 50 gal | 50 gal |
| Tank volume (measured) | 46 gal | 46 gal |
| Uniform Energy Factor | 3.75 | 3.68 |
| First-hour rating | 73 gal | 65 gal |
| Draw pattern | Medium | Medium |
| Yearly energy use | 844 kWh | 883 kWh |
| Heat pump cut-off (low) | 37.4 °F | 37 °F |
| Sound level | 49 dB(A) | 45 dB(A) |
| ENERGY STAR ID | 3531243 | 3417485 |
| Installation | ||
| Power | 240 V | 240 V |
| Circuit | 30 A, 208/240 V | 30 A, 208/240 V |
| Backup element | 4,500 W | 4,500 W |
| Operating air range | 37 to 107 °F | 37 to 120 °F |
| Minimum room size | 700 cu ft | 450 cu ft |
| Size | 66.4 in tall, 21.7 in across | 63 in tall, 15 in across |
| Weight | 218 lb | 196 lb |
| Refrigerant | R-134a | R-134a |
| Features | ||
| Wi-Fi | No | Built in |
| App | - | A. O. Smith (iCOMM) |
| Demand response port (CTA-2045) | - | Yes |
| Leak detection | No | Yes |
| Modes | Economy, Heat Pump, Hybrid, E-Heater, Vacation | Hybrid, Heat Pump, Hot Water+ (3 levels), Guest, Electric, Vacation |
| Warranty and models | ||
| Warranty | 10 yr tank, 10 yr parts, 1 yr labor | 10 yr tank, 10 yr parts, 1 yr labor |
| Also sold as | - | American HPA10250H045DV, Lochinvar HPPA050KD, Reliance 10-50-DHPTA, State HPAX-50-DHPT |
| Released | 2024-08 | 2024-03 |