DoesTheMath

ARISTON ENS30LU-* vs Lennox WHES030L45TN240B****: which uses less energy?

At the low draw pattern the ARISTON ENS30LU-* uses 2,413 kWh a year and the Lennox WHES030L45TN240B**** 2,439 — 26 kWh (1%) less, about 262 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 ENS30LU-* Lennox WHES030L45TN240B****
UEF (Uniform Energy Factor) 0.93 (better) 0.92
Energy use per year (kWh) 2,413 (better) 2,439
First hour rating (gal) 40 40
Rated storage volume (gal) 27 28
Installed cost range $1,467–$1,793 $1,475–$1,602
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

ARISTON ENS30LU-*: 2,413 kWh a year Lennox WHES030L45TN240B****: 2,439 kWh a year

ARISTON ENS30LU-* — 2,413 kWh a year Lennox WHES030L45TN240B**** — 2,439 kWh a year

ARISTON ENS30LU-* is 26 kWh a year lower than Lennox WHES030L45TN240B****.

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

Which should you pick?

  • Pick the ARISTON ENS30LU-* if running cost matters most: it uses 26 kWh less a year on the same test.
  • Pick the Lennox WHES030L45TN240B**** if the installed price matters more than the running cost: its modeled installed range is $1,475–$1,602 against $1,467–$1,793.
  • Neither if your household's busiest hour needs more than 40 gallons of hot water — neither lists more. Check whether a 30-gallon heater is enough.

Each model on its own

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