Both are 46-gallon heat pump water heaters. The HPTS-50-2 is more efficient (UEF 3.80 vs 3.68). The HPTS-50-2 saves $9/year to operate. All figures from published specs and EIA energy prices.
Performance
| Spec | HPTA-50-2 A. O. Smith · Heat Pump | HPTS-50-2 A. O. Smith · Heat Pump |
|---|---|---|
| UEF | 3.68 | 3.80Difference: 0.12 |
| Capacity | 46 galidentical | |
| First Hour Rating | 65 galidentical | |
| kW Input | 4.50 kWidentical | |
The HPTS-50-2 leads on efficiency. But does it fit? Sizing guide
Physical dimensions
| Dimension | HPTA-50-2 | HPTS-50-2 |
|---|---|---|
| Height | 63"identical | |
| Width | 15"Difference: 7" | 22" |
| Depth | — | 22" |
| Weight | 196 lbs | — |
Fit checked. Now the operating cost.
Operating cost
| Cost | HPTA-50-2 | HPTS-50-2 |
|---|---|---|
| Annual Operating Cost | $152/yr | $143/yrDifference: $9/yr |
| 10-Year Operating Cost | $1,520 | $1,430Difference: $90 |
| Annual Energy | 883 kWh | 831 kWhDifference: 52 kWh |
10-year modeled difference is $90. At this scale, local energy rates, usage patterns, and install costs matter more than the efficiency delta.
Costs vary by state. The HPTA-50-2 ranges from $97/yr (ND) to $368/yr (HI). The HPTS-50-2 ranges from $92/yr (ND) to $346/yr (HI).
$9/yr separates them. Install requirements determine the upfront gap. Installation accessories
Installation requirements
| Requirement | HPTA-50-2 | HPTS-50-2 |
|---|---|---|
| Voltage | 240Videntical | |
| Amperage | 22Aidentical | |
| Breaker | 30Aidentical | |
| Condensate Drain | — | Yes |
Same electrical requirements. Swapping between these units should not require electrical changes.
Warranty
| Coverage | HPTA-50-2 | HPTS-50-2 |
|---|---|---|
| Tank | 10 yridentical | |
Features
| Feature | HPTA-50-2 | HPTS-50-2 |
|---|---|---|
| Wi-Fi / Smart | — | Yes |
| Noise Level | — | 45 dB |
| Refrigerant | R-134aidentical | |
Decision split
Pick this one if...
A. O. Smith HPTS-50-2
- You want smart home / Wi-Fi control
- Peak efficiency is the priority (UEF 3.80)
Neither if...
- Your home only has 120V service and you cannot upgrade the panel
- Your install space is under 700 sq ft of open air
Common accessories for this type of installation.
Common install considerations for heat pump units
What is required depends on your existing installation, local code, and installer preference.
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Related
Sources. ENERGY STAR, manufacturer spec sheets, EIA average energy prices.Methodology