DoesTheMath

Mizudo ET011 vs Rheem AM012240T: which uses less energy?

At the very small draw pattern the Rheem AM012240T uses 622 kWh a year and the Mizudo ET011 628 — 7 kWh (1%) less, about 66 kWh over ten years. Both are filed as an electric tankless unit, 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 tankless unit at the very small draw pattern.

Filed and computed figures
Figure Mizudo ET011 Rheem AM012240T
UEF (Uniform Energy Factor) 0.94 0.95 (better)
Energy use per year (kWh) 628 622 (better)
Max flow (GPM) 1.2 1.1
Installed cost range $1,300–$1,790 $1,303–$1,814
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

Mizudo ET011: 628 kWh a year Rheem AM012240T: 622 kWh a year

Mizudo ET011 — 628 kWh a year Rheem AM012240T — 622 kWh a year

Rheem AM012240T is 6 kWh a year lower than Mizudo ET011.

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 Rheem AM012240T if running cost matters most: it uses 7 kWh less a year on the same test.
  • Pick the Mizudo ET011 if you run more fixtures at once: it lists 1.2 GPM against 1.1.
  • Neither if you need more than 1.2 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.

Each model on its own