DoesTheMath

RELIANCE WATER HEATERS ENT-55 1** vs Rheem XE55T12CS55U0: which uses less energy?

At the medium draw pattern the RELIANCE WATER HEATERS ENT-55 1** uses 3,493 kWh a year and the Rheem XE55T12CS55U0 3,531 — 38 kWh (1%) less, about 380 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 medium draw pattern.

Filed and computed figures
RELIANCE WATER HEATERS ENT-55 1** Rheem XE55T12CS55U0
UEF (Uniform Energy Factor) 0.93 (better) 0.92
Energy use per year (kWh) 3,493 (better) 3,531
First hour rating (gal) 72 74
Rated storage volume (gal) 55 55
Installed cost range $1,872–$2,495 $1,866–$2,279
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

RELIANCE WATER HEATERS ENT-55 1**: 3,493 kWh a year Rheem XE55T12CS55U0: 3,531 kWh a year

RELIANCE WATER HEATERS ENT-55 1** — 3,493 kWh a year Rheem XE55T12CS55U0 — 3,531 kWh a year

RELIANCE WATER HEATERS ENT-55 1** is 38 kWh a year lower than Rheem XE55T12CS55U0.

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 RELIANCE WATER HEATERS ENT-55 1** if running cost matters most: it uses 38 kWh less a year on the same test.
  • Pick the Rheem XE55T12CS55U0 if you need more hot water in your busiest hour: it lists a first hour rating of 74 gallons against 72.
  • Neither if your household's busiest hour needs more than 74 gallons of hot water — neither lists more. Check whether a 50-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.