DoesTheMath

NAVIEN NWP500S050AUMB vs Rheem PROPH50 T2 RH375-SO: which uses less energy?

At the medium draw pattern the Rheem PROPH50 T2 RH375-SO uses 837 kWh a year and the NAVIEN NWP500S050AUMB 844 — 7 kWh (1%) less, about 65 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 medium draw pattern.

Filed and computed figures
NAVIEN NWP500S050AUMB Rheem PROPH50 T2 RH375-SO
UEF (Uniform Energy Factor) 3.85 3.88 (better)
Energy use per year (kWh) 844 837 (better)
First hour rating (gal) 65 67
Rated storage volume (gal) 45 45
Installed cost range $3,036–$4,500 $3,039–$4,530
ENERGY STAR certified yes yes
Refrigerant R-134a, GWP 1430 R-134a, GWP 1430
On the market since 2025-04-30 2022-12-05
DOE CCD · 2026-09-19

What it costs to run

NAVIEN NWP500S050AUMB: 844 kWh a year Rheem PROPH50 T2 RH375-SO: 837 kWh a year

NAVIEN NWP500S050AUMB — 844 kWh a year Rheem PROPH50 T2 RH375-SO — 837 kWh a year

Rheem PROPH50 T2 RH375-SO is 7 kWh a year lower than NAVIEN NWP500S050AUMB.

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 NWP500S050AUMB since 2025-04-30, the Rheem PROPH50 T2 RH375-SO since 2022-12-05. A sale date, not a lifespan.

Which should you pick?

  • Pick the Rheem PROPH50 T2 RH375-SO if running cost matters most: it uses 7 kWh less a year on the same test.
  • Pick the NAVIEN NWP500S050AUMB if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the Rheem PROPH50 T2 RH375-SO.
  • Neither if your household's busiest hour needs more than 67 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.

Each model on its own

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