Both are heat pump water heaters. Efficiency is nearly identical. The PROPH80 T2 RH400-30 saves $9/year to operate. All figures from published specs and EIA energy prices.
Performance
| Spec | NWP500S080AUMB Navien · Heat Pump | PROPH80 T2 RH400-30 Rheem · Heat Pump |
|---|---|---|
| UEF | 4.05 | 4.07Difference: 0.02 |
| Capacity | 74 galDifference: 2 gal | 72 gal |
| First Hour Rating | 85 gal | 87 galDifference: 2 gal |
| kW Input | 5 kW | 4.50 kWDifference: 0.50 kW |
But does it fit? Sizing guide
Physical dimensions
| Dimension | NWP500S080AUMB | PROPH80 T2 RH400-30 |
|---|---|---|
| Height | 71.60"Difference: 2.59" | 74.19" |
| Width | 25" | 24.25"Difference: 0.75" |
| Depth | 25" | 24.62"Difference: 0.38" |
| Weight | 220 lbsDifference: 41 lbs | 261 lbs |
The PROPH80 T2 RH400-30 is taller. Fit checked. Now the operating cost.
Operating cost
| Cost | NWP500S080AUMB | PROPH80 T2 RH400-30 |
|---|---|---|
| Annual Operating Cost | $218/yr | $209/yrDifference: $9/yr |
| 10-Year Operating Cost | $2,180 | $2,090Difference: $90 |
| Annual Energy | 1,265 kWh | 1,213 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 NWP500S080AUMB ranges from $139/yr (ND) to $526/yr (HI). The PROPH80 T2 RH400-30 ranges from $134/yr (ND) to $505/yr (HI).
$9/yr separates them. Install requirements determine the upfront gap. Installation accessories
Installation requirements
| Requirement | NWP500S080AUMB | PROPH80 T2 RH400-30 |
|---|---|---|
| Voltage | 240Videntical | |
| Amperage | 23A | 21ADifference: 2A |
| Breaker | 30Aidentical | |
| Condensate Drain | Yes | — |
Same electrical requirements. Swapping between these units should not require electrical changes.
Warranty
| Coverage | NWP500S080AUMB | PROPH80 T2 RH400-30 |
|---|---|---|
| Tank | 10 yridentical | |
| Parts | 10 yridentical | |
| Labor | 1 yr | — |
Features
| Feature | NWP500S080AUMB | PROPH80 T2 RH400-30 |
|---|---|---|
| Wi-Fi / Smart | Yesidentical | |
| Noise Level | 45 dB | — |
| Refrigerant | R-134aidentical | |
Decision split
Pick this one if...
Navien NWP500S080AUMB
- Your ceiling or space is under 74.19"
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