The NWP500S050AUMB is more efficient (UEF 3.85 vs 0.96). The NWP500S050AUMB saves $94/year to operate. All figures from published specs and EIA energy prices.
Performance
| Spec | NPE-210S2 Navien · Condensing Tankless | NWP500S050AUMB Navien · Heat Pump |
|---|---|---|
| UEF | 0.96 | 3.85Difference: 2.89 |
| Capacity | — | 44 gal |
| First Hour Rating | — | 65 gal |
| Max Flow Rate | 5.30 GPM | — |
| BTU Input | 180,000 | — |
| kW Input | — | 5 kW |
The NWP500S050AUMB leads on efficiency. But does it fit? Sizing guide
Physical dimensions
| Dimension | NPE-210S2 | NWP500S050AUMB |
|---|---|---|
| Height | 27.40"Difference: 35.60" | 63" |
| Width | 17.30"Difference: 4.40" | 21.70" |
| Depth | 13.20"Difference: 8.50" | 21.70" |
| Weight | 73 lbsDifference: 108 lbs | 181 lbs |
The NWP500S050AUMB is taller. Fit checked. Now the operating cost.
Operating cost
| Cost | NPE-210S2 | NWP500S050AUMB |
|---|---|---|
| Annual Operating Cost | $239/yr | $145/yrDifference: $94/yr |
| 10-Year Operating Cost | $2,390 | $1,450Difference: $940 |
| Annual Energy | — | 840 kWh |
10-year difference: $940 in favor of the NWP500S050AUMB, at current US average energy rates. Actual savings depend on local rates and usage patterns.
Costs vary by state. The NPE-210S2 ranges from $116/yr (ID) to $878/yr (HI). The NWP500S050AUMB ranges from $93/yr (ND) to $350/yr (HI).
$94/yr separates them. Install requirements determine the upfront gap. Installation accessories
Installation requirements
| Requirement | NPE-210S2 | NWP500S050AUMB |
|---|---|---|
| Voltage | 120VDifference: 120V | 240V |
| Amperage | 5ADifference: 18A | 23A |
| Breaker | 15ADifference: 15A | 30A |
| Vent Type | Direct Vent | — |
| Vent Material | Category Iv Pvc Cpvc | — |
| Condensate Drain | — | Yes |
Install impact: different voltage (120V vs 240V); different breaker size (15A vs 30A). Switching between these units may affect your utility room setup.
Warranty
| Coverage | NPE-210S2 | NWP500S050AUMB |
|---|---|---|
| Tank | — | 10 yr |
| Heat Exchanger | 15 yr | — |
| Parts | 5 yr | 10 yrDifference: 5 yr |
| Labor | — | 1 yr |
Features
| Feature | NPE-210S2 | NWP500S050AUMB |
|---|---|---|
| Wi-Fi / Smart | — | Yes |
| Noise Level | — | 45 dB |
| Refrigerant | — | R-134a |
Decision split
Pick this one if...
Navien NPE-210S2
- Your ceiling or space is under 63"
- Your panel already has 120V service
Pick this one if...
Navien NWP500S050AUMB
- Your panel already has 240V service
- Minimizing energy cost matters (saves $94/yr)
- You want smart home / Wi-Fi control
- Peak efficiency is the priority (UEF 3.85)
If you have decided, here is what the install requires.
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