Navien NWP500 40-Gallon vs Rinnai REHP80BM 80-Gallon
The Rinnai REHP80BM 80-Gallon is the more efficient unit: UEF 4 versus 3.85 — about 4% less energy for the same hot water. At national average rates that works out to about $143/year for the Navien NWP500 40-Gallon against $208/year for the Rinnai REHP80BM 80-Gallon — a $65 annual difference. The Rinnai REHP80BM 80-Gallon delivers more hot water in the peak hour (91 gal first-hour rating vs 65 gal).
| Navien NWP500 40-Gallon | Rinnai REHP80BM 80-Gallon | |
|---|---|---|
| Uniform Energy Factor (UEF) | 3.85 | 4 |
| Fuel | Electric | Electric |
| First-hour rating | 65 gal | 91 gal |
| Rated storage volume | 44 gal | 75 gal |
| Draw pattern | Medium | High |
| Annual electricity use | 840 kWh/yr | 1225 kWh/yr |
| Heat pump type | 240 Volt Integrated HPWH | 240 Volt Integrated HPWH |
| Input voltage | 240 | 240 |
| Max current draw | 23 A | 24 A |
| Recovery efficiency | 461 % | 454 % |
| Smart / connected capable | No | No |
| Refrigerant (GWP) | R-134a (GWP:1430) | R-134a (GWP:1430) |
| Compressor low-temp cutoff | 41 °F | 37.4 °F |
| Height | 63 in | 74.2 in |
| Diameter | 21.8 in | 25.7 in |
| ENERGY STAR certified | Yes | Yes |
Frequently asked questions
Which costs less to run, the Navien NWP500 40-Gallon or the Rinnai REHP80BM 80-Gallon?
The Navien NWP500 40-Gallon: about $143/year versus $208/year for the Rinnai REHP80BM 80-Gallon at national average rates — a $65 annual difference.
Are the Navien NWP500 40-Gallon and Rinnai REHP80BM 80-Gallon both ENERGY STAR certified?
Yes — every water heater in this database is drawn from the U.S. EPA ENERGY STAR certified water heater datasets.