DoesTheMath

ARISTON ARIHPWH-50 vs Richmond PROPH50 T2 RH375-SO: which uses less energy?

At the medium draw pattern the Richmond PROPH50 T2 RH375-SO uses 837 kWh a year and the ARISTON ARIHPWH-50 866 — 29 kWh (3%) less, about 290 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
ARISTON ARIHPWH-50 Richmond PROPH50 T2 RH375-SO
UEF (Uniform Energy Factor) 3.75 3.88 (better)
Energy use per year (kWh) 866 837 (better)
First hour rating (gal) 68 67
Rated storage volume (gal) 45 45
Installed cost range $3,024–$4,400 $3,039–$4,530
ENERGY STAR certified yes yes
Refrigerant R-134a, GWP 1430 R-134a, GWP 1430
On the market since 2024-12-13 2023-03-31
DOE CCD · 2026-09-19

What it costs to run

ARISTON ARIHPWH-50: 866 kWh a year Richmond PROPH50 T2 RH375-SO: 837 kWh a year

ARISTON ARIHPWH-50 — 866 kWh a year Richmond PROPH50 T2 RH375-SO — 837 kWh a year

Richmond PROPH50 T2 RH375-SO is 29 kWh a year lower than ARISTON ARIHPWH-50.

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 ARISTON ARIHPWH-50 since 2024-12-13, the Richmond PROPH50 T2 RH375-SO since 2023-03-31. A sale date, not a lifespan.

Which should you pick?

  • Pick the Richmond PROPH50 T2 RH375-SO if running cost matters most: it uses 29 kWh less a year on the same test.
  • Pick the ARISTON ARIHPWH-50 if you need more hot water in your busiest hour: it lists a first hour rating of 68 gallons against 67.
  • Neither if your household's busiest hour needs more than 68 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.

Each model on its own

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