DoesTheMath

A. O. SMITH HPTA-50 2** vs Ruud PROPH65 T0 RH120-M: which uses less energy?

At the medium draw pattern the A. O. SMITH HPTA-50 2** uses 883 kWh a year and the Ruud PROPH65 T0 RH120-M 1,041 — 158 kWh (15%) less, about 1,584 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
A. O. SMITH HPTA-50 2** Ruud PROPH65 T0 RH120-M
UEF (Uniform Energy Factor) 3.68 (better) 3.12
Energy use per year (kWh) 883 (better) 1,041
First hour rating (gal) 65 63
Rated storage volume (gal) 46 59
Installed cost range $3,049–$4,340 $3,406–$3,902
ENERGY STAR certified yes yes
Refrigerant R-134a, GWP 1430 R-134a, GWP 1430
On the market since 2024-03-01 2022-04-21
DOE CCD · 2026-09-19

What it costs to run

A. O. SMITH HPTA-50 2**: 883 kWh a year Ruud PROPH65 T0 RH120-M: 1,041 kWh a year

A. O. SMITH HPTA-50 2** — 883 kWh a year Ruud PROPH65 T0 RH120-M — 1,041 kWh a year

A. O. SMITH HPTA-50 2** is 158 kWh a year lower than Ruud PROPH65 T0 RH120-M.

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 A. O. SMITH HPTA-50 2** since 2024-03-01, the Ruud PROPH65 T0 RH120-M since 2022-04-21. A sale date, not a lifespan.

Which should you pick?

  • Pick the A. O. SMITH HPTA-50 2** if running cost matters most: it uses 158 kWh less a year on the same test.
  • Pick the Ruud PROPH65 T0 RH120-M if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the A. O. SMITH HPTA-50 2**.
  • Neither if your household's busiest hour needs more than 65 gallons of hot water — neither lists more. Check whether a 50-gallon heater is enough.

Each model on its own

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