A.O. Smith Voltex MAX 66 Gal
#3 in 65 GallonFull review
A solid 240 V heater with leak protection included, sold at Lowe’s as the Signature 900 line.
Lowe's $2,579$2,579
3.7/5
Navien’s stainless-tank hybrid, sold through plumbers, with a 10-year warranty that includes a year of labor. Its heat pump stops below 41 °F room air, so it suits a basement more than a cold garage.
- 65 galSize
- 4.03UEF
- 80 galFirst hour
- 240 VPower
- 41 °FRuns down to
- 10 yr tankWarranty
See it at Navien
No store we check sells it online; the maker lists where to buy or who installs it.
Pros
- Stainless steel tank instead of glass-lined steel
- Very efficient: a certified UEF of 4.03, about a quarter of the electricity of a standard electric tank
- Delivers 80 gallons of hot water in the first hour, a lot for its size
Cons
- Switches to the backup element when the room drops below 41 °F, so it saves little in a freezing garage
How it scores
The rating comes from 5 measured or published factors, each scored 0-100 against fixed reference points for its size. How we rank explains each one.
Specifications
| Model number | NWP500S065AUMB |
|---|---|
| Ratings (ENERGY STAR) | |
| Size (nominal) | 65 gal |
| Tank volume (measured) | 61 gal |
| Uniform Energy Factor | 4.03 |
| First-hour rating | 80 gal |
| Draw pattern | High |
| Yearly energy use | 1,245 kWh |
| Heat pump cut-off (low) | 41 °F |
| ENERGY STAR ID | 4015937 |
| Installation | |
| Power | 240 V |
| Circuit | 30 A, 208/240 V |
| Backup element | 5,000 W |
| Operating air range | 41 to 113 °F |
| Minimum room size | 640 cu ft |
| Size | 63 in tall, 25 in across |
| Weight | 204 lb |
| Refrigerant | R-134a |
| Features | |
| Wi-Fi | Built in |
| App | NaviLink |
| Leak detection | No |
| Modes | Energy Saver, Heat Pump, High Demand, Electric, Vacation |
| Warranty and models | |
| Warranty | 10 yr tank, 10 yr parts, 1 yr labor |
| Released | 2025-06 |
Alternatives in this size
Rheem ProTerra 65 Gal
#4 in 65 GallonFull review
A strong 240 V choice with Wi-Fi, widely stocked at Home Depot. GE Profile beats it on efficiency and noise.
Home Depot $2,289$2,289
LG Inverter Heat Pump 58 Gal
#6 in 65 GallonFull review
The pick for a cold garage or basement: its heat pump keeps working in rooms down to 23 °F. Sold through LG’s HVAC dealers.
Compare
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