Navien NWP500 40-Gallon vs State Heat Pump 65-Gallon (HPAX-66-DHPT 2)
The Navien NWP500 40-Gallon is the more efficient unit: UEF 3.85 versus 3.84 — about 0% 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 $220/year for the State Heat Pump 65-Gallon (HPAX-66-DHPT 2) — a $77 annual difference. The State Heat Pump 65-Gallon (HPAX-66-DHPT 2) delivers more hot water in the peak hour (83 gal first-hour rating vs 65 gal). Only the State Heat Pump 65-Gallon (HPAX-66-DHPT 2) is connected-capable (app control, utility programs).
| Navien NWP500 40-Gallon | State Heat Pump 65-Gallon (HPAX-66-DHPT 2) | |
|---|---|---|
| Uniform Energy Factor (UEF) | 3.85 | 3.84 |
| Fuel | Electric | Electric |
| First-hour rating | 65 gal | 83 gal |
| Rated storage volume | 44 gal | 68 gal |
| Draw pattern | Medium | High |
| Annual electricity use | 840 kWh/yr | 1292 kWh/yr |
| Heat pump type | 240 Volt Integrated HPWH | 240 Volt Integrated HPWH |
| Input voltage | 240 | 240 |
| Max current draw | 23 A | 22 A |
| Recovery efficiency | 461 % | 435 % |
| Smart / connected capable | No | Yes |
| Refrigerant (GWP) | R-134a (GWP:1430) | R-134a (GWP:1430) |
| Compressor low-temp cutoff | 41 °F | 37 °F |
| Height | 63 in | 61 in |
| Diameter | 21.8 in | 23 in |
| ENERGY STAR certified | Yes | Yes |
Frequently asked questions
Which costs less to run, the Navien NWP500 40-Gallon or the State Heat Pump 65-Gallon (HPAX-66-DHPT 2)?
The Navien NWP500 40-Gallon: about $143/year versus $220/year for the State Heat Pump 65-Gallon (HPAX-66-DHPT 2) at national average rates — a $77 annual difference.
Are the Navien NWP500 40-Gallon and State Heat Pump 65-Gallon (HPAX-66-DHPT 2) both ENERGY STAR certified?
Yes — every water heater in this database is drawn from the U.S. EPA ENERGY STAR certified water heater datasets.