DoesTheMath

MRCOOL MEWH30S82S1 vs RELIANCE WATER HEATERS ENS-30 1**: which uses less energy?

At the low draw pattern the MRCOOL MEWH30S82S1 uses 2,439 kWh a year and the RELIANCE WATER HEATERS ENS-30 1** 2,522 — 82 kWh (3%) less, about 822 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
MRCOOL MEWH30S82S1 RELIANCE WATER HEATERS ENS-30 1**
UEF (Uniform Energy Factor) 0.92 (better) 0.89
Energy use per year (kWh) 2,439 (better) 2,522
First hour rating (gal) 47 47
Rated storage volume (gal) 28 27
Installed cost range $1,475–$1,602 not published
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

MRCOOL MEWH30S82S1: 2,439 kWh a year RELIANCE WATER HEATERS ENS-30 1**: 2,522 kWh a year

MRCOOL MEWH30S82S1 — 2,439 kWh a year RELIANCE WATER HEATERS ENS-30 1** — 2,522 kWh a year

MRCOOL MEWH30S82S1 is 83 kWh a year lower than RELIANCE WATER HEATERS ENS-30 1**.

DOE CCD · 2026-09-19

Report an issue with this number

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 MRCOOL MEWH30S82S1 if running cost matters most: it uses 82 kWh less a year on the same test.
  • Pick the RELIANCE WATER HEATERS ENS-30 1** if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the MRCOOL MEWH30S82S1.
  • Neither if your household's busiest hour needs more than 47 gallons of hot water — neither lists more. Check whether a 30-gallon heater is enough.

Each model on its own

Analytics cookies

We count page views without cookies for everyone, and that counter is what we use to decide what to build. Google Analytics is separate: it uses cookies to record how a page was used, and it loads only if you allow it. Decline and the site works exactly the same. What we collect.