NAVIEN NWP500S080AUMB vs Ruud PROPH80 T2 RH375-SO: which uses less energy?

At the high draw pattern the Ruud PROPH80 T2 RH375-SO uses 1,219 kWh a year and the NAVIEN NWP500S080AUMB 1,225 — 6 kWh (0%) less, about 60 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
Figure	NAVIEN NWP500S080AUMB	Ruud PROPH80 T2 RH375-SO
UEF (Uniform Energy Factor)	4.05	4.07 (better)
Energy use per year (kWh)	1,225	1,219 (better)
First hour rating (gal)	85	87
Rated storage volume (gal)	74	72
Installed cost range	$3,999–$4,974	$3,936–$4,975
ENERGY STAR certified	yes	yes
Refrigerant	R-134a, GWP 1430	R-134a, GWP 1430
On the market since	2025-04-30	2024-06-24

DOE CCD · 2026-09-19

What it costs to run

NAVIEN NWP500S080AUMB — 1,225 kWh a year Ruud PROPH80 T2 RH375-SO — 1,219 kWh a year

Ruud PROPH80 T2 RH375-SO is 6 kWh a year lower than NAVIEN NWP500S080AUMB.

DOE CCD · 2026-09-19

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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 NWP500S080AUMB since 2025-04-30, the Ruud PROPH80 T2 RH375-SO since 2024-06-24. A sale date, not a lifespan.

Which should you pick?

Pick the Ruud PROPH80 T2 RH375-SO if running cost matters most: it uses 6 kWh less a year on the same test.
Pick the NAVIEN NWP500S080AUMB if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the Ruud PROPH80 T2 RH375-SO.
Neither if your household's busiest hour needs more than 87 gallons of hot water — neither lists more. Check whether a 75-gallon heater is enough.

Each model on its own

NAVIEN NWP500S080AUMB

Its filed figures, class position and running cost on your ZIP.
Ruud PROPH80 T2 RH375-SO

Its filed figures, class position and running cost on your ZIP.