DoesTheMath

ARISTON ARIHPWH-65 vs Lennox WHHP065T45MD240S****: which uses less energy?

At the high draw pattern the Lennox WHHP065T45MD240S**** uses 1,225 kWh a year and the ARISTON ARIHPWH-65 1,289 — 64 kWh (5%) less, about 636 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 Lennox WHHP065T45MD240S****
UEF (Uniform Energy Factor) 3.85 4.05 (better)
Energy use per year (kWh) 1,289 1,225 (better)
First hour rating (gal) 78 77
Rated storage volume (gal) 62 61
Installed cost range $3,587–$4,661 $3,577–$4,851
ENERGY STAR certified yes yes
Refrigerant R-134a, GWP 1430 R-513A, GWP 630
On the market since 2024-12-13 2025-12-01
DOE CCD · 2026-09-19

What it costs to run

ARISTON ARIHPWH-65: 1,289 kWh a year Lennox WHHP065T45MD240S****: 1,225 kWh a year

ARISTON ARIHPWH-65 — 1,289 kWh a year Lennox WHHP065T45MD240S**** — 1,225 kWh a year

Lennox WHHP065T45MD240S**** is 64 kWh a year lower than ARISTON ARIHPWH-65.

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 since 2024-12-13, the Lennox WHHP065T45MD240S**** since 2025-12-01. A sale date, not a lifespan.

Which should you pick?

  • Pick the Lennox WHHP065T45MD240S**** if running cost matters most: it uses 64 kWh less a year on the same test.
  • Pick the ARISTON ARIHPWH-65 if you need more hot water in your busiest hour: it lists a first hour rating of 78 gallons against 77.
  • Neither if your household's busiest hour needs more than 78 gallons of hot water — neither lists more. Check whether a 65-gallon heater is enough.

Each model on its own

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