A.O. Smith Voltex MAX 80 Gal
#3 in 80 GallonFull review
A solid 240 V heater with leak protection included, sold at Lowe’s as the Signature 900 line.
Lowe's $2,999$2,999
The A.O. Smith Voltex MAX 80 Gal is the better heat pump water heater overall, rated 3.8 to 3.6. The A.O. Smith Voltex MAX 80 Gal leads on hot water and noise. The Ariston NUOS Side-Connect 80 Gal wins on efficiency and cold rooms.
Ariston NUOS Side-Connect 80 Gal
#11 in 80 GallonFull review
A non-Midea design with a leak sensor built in and a 10-year tank and parts warranty, sold through plumbing dealers. It is louder than most here.
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 A.O. Smith Voltex MAX 80 Gal for hot water (95 gallons in the first hour vs 87 gallons in the first hour) and noise (45 dB(A) vs 49.1 dB(A)).
- Choose the Ariston NUOS Side-Connect 80 Gal for efficiency (4.01 UEF vs 3.88 UEF) and cold rooms (heat pump runs down to 35 °F room air vs heat pump runs down to 37 °F room air).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 80 gallon heat pump water heater; a clear win is highlighted. How we rank explains each one.
| Factor weight | A.O. Smith Voltex MAX 80 Gal | Ariston NUOS Side-Connect 80 Gal |
|---|---|---|
| Overall rating | 3.8/5 | 3.6/5 |
| Efficiency 35% | 63 3.88 UEF | 72 4.01 UEF |
| Hot water 20% | 80 95 gallons in the first hour | 48 87 gallons in the first hour |
| Warranty 20% | 75 10-year tank, 10-year parts, 1-year labor | 70 10-year tank, 10-year parts |
| Cold rooms 15% | 32 heat pump runs down to 37 °F room air | 40 heat pump runs down to 35 °F room air |
| Noise 10% | 69 45 dB(A) | 43 49.1 dB(A) |
Specifications
| A.O. Smith Voltex MAX 80 Gal | Ariston NUOS Side-Connect 80 Gal | |
|---|---|---|
| Ratings (ENERGY STAR) | ||
| Size (nominal) | 80 gal | 80 gal |
| Tank volume (measured) | 81 gal | 73 gal |
| Uniform Energy Factor | 3.88 | 4.01 |
| First-hour rating | 95 gal | 87 gal |
| Draw pattern | High | High |
| Yearly energy use | 1,279 kWh | 1,238 kWh |
| Heat pump cut-off (low) | 37 °F | 35 °F |
| Sound level | 45 dB(A) | 49.1 dB(A) |
| ENERGY STAR ID | 3417562 | 3942615 |
| 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 120 °F | 36 to 120 °F |
| Minimum room size | 450 cu ft | 700 cu ft |
| Size | 69 in tall, 27 in across | 59.1 in tall, 20.2 in across |
| Weight | 302 lb | - |
| Refrigerant | R-134a | R-134a |
| Features | ||
| Wi-Fi | Built in | Built in |
| App | A. O. Smith (iCOMM) | Ariston NET |
| Demand response port (CTA-2045) | Yes | Yes |
| Leak detection | Yes | Yes |
| Modes | Hybrid, Heat Pump, Hot Water+ (3 levels), Guest, Electric, Vacation | Comfort, Green, Fast, Electric, Vacation |
| Warranty and models | ||
| Warranty | 10 yr tank, 10 yr parts, 1 yr labor | 10 yr tank, 10 yr parts |
| Also sold as | American HPA10280H045DV, Lochinvar HPPA080KD, Reliance 10-80-DHPTA, State HPAX-80-DHPT | American Standard ASHPWH-80*****, Lennox WHHP080T45MD240S**** |
| Released | 2024-03 | 2024-12 |