DoesTheMath

ARISTON ARIHPWH-65-T vs RINNAI REHP65W*: which uses less energy?

At the high draw pattern the ARISTON ARIHPWH-65-T uses 1,225 kWh a year and the RINNAI REHP65W* 1,240 — 15 kWh (1%) less, about 153 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
ARISTON ARIHPWH-65-T RINNAI REHP65W*
UEF (Uniform Energy Factor) 4.05 (better) 4
Energy use per year (kWh) 1,225 (better) 1,240
First hour rating (gal) 77 80
Rated storage volume (gal) 61 61
Installed cost range $3,577–$4,851 $3,572–$4,801
ENERGY STAR certified yes yes
Sound level (dB) not filed 49
Refrigerant R-513A, GWP 630 R-134a, GWP 1430
On the market since 2025-06-01 2026-06-30
DOE CCD · 2026-09-19

What it costs to run

ARISTON ARIHPWH-65-T: 1,225 kWh a year RINNAI REHP65W*: 1,240 kWh a year

ARISTON ARIHPWH-65-T — 1,225 kWh a year RINNAI REHP65W* — 1,240 kWh a year

ARISTON ARIHPWH-65-T is 15 kWh a year lower than RINNAI REHP65W*.

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.
  • 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-65-T since 2025-06-01, the RINNAI REHP65W* since 2026-06-30. A sale date, not a lifespan.

Which should you pick?

  • Pick the ARISTON ARIHPWH-65-T if running cost matters most: it uses 15 kWh less a year on the same test.
  • Pick the RINNAI REHP65W* if you need more hot water in your busiest hour: it lists a first hour rating of 80 gallons against 77.
  • Neither if your household's busiest hour needs more than 80 gallons of hot water — neither lists more. Check whether a 65-gallon heater is enough.

Each model on its own

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