DoesTheMath

AMERICAN HPTA-50 2** vs NAVIEN NWP500S050AUMB: which uses less energy?

At the medium draw pattern the NAVIEN NWP500S050AUMB uses 844 kWh a year and the AMERICAN HPTA-50 2** 883 — 39 kWh (4%) less, about 390 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
AMERICAN HPTA-50 2** NAVIEN NWP500S050AUMB
UEF (Uniform Energy Factor) 3.68 3.85 (better)
Energy use per year (kWh) 883 844 (better)
First hour rating (gal) 65 65
Rated storage volume (gal) 46 45
Installed cost range $3,049–$4,340 $3,036–$4,500
ENERGY STAR certified yes yes
Refrigerant R-134a, GWP 1430 R-134a, GWP 1430
On the market since 2024-03-01 2025-04-30
DOE CCD · 2026-09-19

What it costs to run

AMERICAN HPTA-50 2**: 883 kWh a year NAVIEN NWP500S050AUMB: 844 kWh a year

AMERICAN HPTA-50 2** — 883 kWh a year NAVIEN NWP500S050AUMB — 844 kWh a year

NAVIEN NWP500S050AUMB is 39 kWh a year lower than AMERICAN HPTA-50 2**.

DOE CCD · 2026-09-19

Report an issue with this number

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 AMERICAN HPTA-50 2** since 2024-03-01, the NAVIEN NWP500S050AUMB since 2025-04-30. A sale date, not a lifespan.

Which should you pick?

  • Pick the NAVIEN NWP500S050AUMB if running cost matters most: it uses 39 kWh less a year on the same test.
  • Pick the AMERICAN HPTA-50 2** if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the NAVIEN NWP500S050AUMB.
  • Neither if your household's busiest hour needs more than 65 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.

Each model on its own

Analytics cookies

We count page views without cookies for everyone, and that counter is what we use to decide what to build. Google Analytics is separate: it uses cookies to record how a page was used, and it loads only if you allow it. Decline and the site works exactly the same. What we collect.