DoesTheMath

NAVIEN NWP500S065AUMB vs RINNAI REHP65BM: which uses less energy?

At the high draw pattern the NAVIEN NWP500S065AUMB uses 1,231 kWh a year and the RINNAI REHP65BM 1,272 — 41 kWh (3%) less, about 410 kWh over ten years. Both are filed as an electric tank, so the comparison holds. Enter your ZIP below to price the difference.

Side by side

Compared within one class only: models filed as an electric tank at the high draw pattern.

Filed and computed figures
NAVIEN NWP500S065AUMB RINNAI REHP65BM
UEF (Uniform Energy Factor) 4.03 (better) 3.9
Energy use per year (kWh) 1,231 (better) 1,272
First hour rating (gal) 80 80
Rated storage volume (gal) 61 60
Installed cost range $3,575–$4,831 $3,528–$4,692
ENERGY STAR certified yes yes
Sound level (dB) not filed 49
Refrigerant R-134a, GWP 1430 R-134a, GWP 1430
On the market since 2025-04-30 2024-09-13
DOE CCD · 2026-09-19

What it costs to run

NAVIEN NWP500S065AUMB: 1,231 kWh a year RINNAI REHP65BM: 1,272 kWh a year

NAVIEN NWP500S065AUMB — 1,231 kWh a year RINNAI REHP65BM — 1,272 kWh a year

NAVIEN NWP500S065AUMB is 41 kWh a year lower than RINNAI REHP65BM.

DOE CCD · 2026-09-19

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Enter your ZIP to price both units on the same rate where you live.

Reliability

Not published: Reliability, failure rates and each model’s actual warranty term.

The registries these figures come from certify energy performance under a federal test; none of them records how long a unit lasts or how often it fails, so this page does not rank the two on reliability.

What is here instead:

  • The filed efficiency, capacity and tank size of both models, side by side below.
  • Both are ENERGY STAR certified, which requires a manufacturer warranty of at least six years; the actual term for each model is not published.
  • Time on the market, as filed with ENERGY STAR: the NAVIEN NWP500S065AUMB since 2025-04-30, the RINNAI REHP65BM since 2024-09-13. A sale date, not a lifespan.

Which should you pick?

  • Pick the NAVIEN NWP500S065AUMB if running cost matters most: it uses 41 kWh less a year on the same test.
  • Pick the RINNAI REHP65BM if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the NAVIEN NWP500S065AUMB.
  • Neither if your household's busiest hour needs more than 80 gallons of hot water — neither lists more. Check whether a 65-gallon heater is enough.

Each model on its own

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