Both are heat pump water heaters. The REHP65 is more efficient (UEF 3.90 vs 3.84). The REHP65 saves $9/year to operate. All figures from published specs and EIA energy prices.
Performance
| Spec | HPTA-66-2 A. O. Smith · Heat Pump | REHP65 Rinnai · Heat Pump |
|---|---|---|
| UEF | 3.84 | 3.90Difference: 0.06 |
| Capacity | 68 galDifference: 8 gal | 60 gal |
| First Hour Rating | 83 galDifference: 3 gal | 80 gal |
| kW Input | 4.50 kWDifference: 1 kW | 5.50 kW |
The REHP65 leads on efficiency. But does it fit? Sizing guide
Physical dimensions
| Dimension | HPTA-66-2 | REHP65 |
|---|---|---|
| Height | 61"Difference: 4.50" | 65.50" |
| Width | 23"Difference: 2.60" | 25.60" |
| Weight | — | 271 lbs |
The REHP65 is taller. Fit checked. Now the operating cost.
Operating cost
| Cost | HPTA-66-2 | REHP65 |
|---|---|---|
| Annual Operating Cost | $223/yr | $214/yrDifference: $9/yr |
| 10-Year Operating Cost | $2,230 | $2,140Difference: $90 |
| Annual Energy | 1,292 kWh | 1,240 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-66-2 ranges from $142/yr (ND) to $538/yr (HI). The REHP65 ranges from $137/yr (ND) to $516/yr (HI).
$9/yr separates them. Install requirements determine the upfront gap. Installation accessories
Installation requirements
| Requirement | HPTA-66-2 | REHP65 |
|---|---|---|
| Voltage | 240Videntical | |
| Amperage | 22ADifference: 2A | 24A |
| Breaker | — | 30A |
Same electrical requirements. Swapping between these units should not require electrical changes.
Warranty
| Coverage | HPTA-66-2 | REHP65 |
|---|---|---|
| Tank | 10 yridentical | |
| Parts | — | 10 yr |
| Labor | — | 1 yr |
Features
| Feature | HPTA-66-2 | REHP65 |
|---|---|---|
| Wi-Fi / Smart | — | No |
| Refrigerant | R-134aidentical | |
Decision split
Pick this one if...
A. O. Smith HPTA-66-2
- Your ceiling or space is under 65.50"
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