DoesTheMath

ARISTON ENS30LUB 240V-3500W vs Ruud MR30245 C: which uses less energy?

At the low draw pattern the ARISTON ENS30LUB 240V-3500W uses 2,439 kWh a year and the Ruud MR30245 C 2,550 — 111 kWh (4%) less, about 1,109 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 low draw pattern.

Filed and computed figures
ARISTON ENS30LUB 240V-3500W Ruud MR30245 C
UEF (Uniform Energy Factor) 0.92 (better) 0.88
Energy use per year (kWh) 2,439 (better) 2,550
First hour rating (gal) 35 37
Rated storage volume (gal) 27 28
Installed cost range $1,461–$1,577 not published
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

ARISTON ENS30LUB 240V-3500W: 2,439 kWh a year Ruud MR30245 C: 2,550 kWh a year

ARISTON ENS30LUB 240V-3500W — 2,439 kWh a year Ruud MR30245 C — 2,550 kWh a year

ARISTON ENS30LUB 240V-3500W is 111 kWh a year lower than Ruud MR30245 C.

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 ARISTON ENS30LUB 240V-3500W if running cost matters most: it uses 111 kWh less a year on the same test.
  • Pick the Ruud MR30245 C if you need more hot water in your busiest hour: it lists a first hour rating of 37 gallons against 35.
  • Neither if your household's busiest hour needs more than 37 gallons of hot water — neither lists more. Check whether a 30-gallon heater is enough.

Each model on its own

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