DoesTheMath

Rheem PROPH65 T0 RH120-M vs Stiebel Eltron Accelera 300 E: which uses less energy?

At the medium draw pattern the Stiebel Eltron Accelera 300 E uses 1,025 kWh a year and the Rheem PROPH65 T0 RH120-M 1,041 — 16 kWh (2%) less, about 164 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
Rheem PROPH65 T0 RH120-M Stiebel Eltron Accelera 300 E
UEF (Uniform Energy Factor) 3.12 3.17 (better)
Energy use per year (kWh) 1,041 1,025 (better)
First hour rating (gal) 63 66
Rated storage volume (gal) 59 58
Installed cost range $3,406–$3,902 $3,379–$3,943
ENERGY STAR certified yes not matched
Refrigerant R-134a, GWP 1430 not filed
On the market since 2022-04-21 not filed
DOE CCD · 2026-09-19

What it costs to run

Rheem PROPH65 T0 RH120-M: 1,041 kWh a year Stiebel Eltron Accelera 300 E: 1,025 kWh a year

Rheem PROPH65 T0 RH120-M — 1,041 kWh a year Stiebel Eltron Accelera 300 E — 1,025 kWh a year

Stiebel Eltron Accelera 300 E is 16 kWh a year lower than Rheem PROPH65 T0 RH120-M.

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.
  • The actual warranty term is printed in each model’s documentation, not in any registry.

Which should you pick?

  • Pick the Stiebel Eltron Accelera 300 E if running cost matters most: it uses 16 kWh less a year on the same test.
  • Pick the Rheem 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 Stiebel Eltron Accelera 300 E.
  • Neither if your household's busiest hour needs more than 66 gallons of hot water — neither lists more.

Each model on its own

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