DoesTheMath

EEMAX AM005240T vs Rheem SPEX55T: which uses less energy?

At the very small draw pattern the Rheem SPEX55T uses 609 kWh a year and the EEMAX AM005240T 615 — 6 kWh (1%) less, about 63 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 EEMAX AM005240T Rheem SPEX55T
UEF (Uniform Energy Factor) 0.96 0.97 (better)
Energy use per year (kWh) 615 609 (better)
Max flow (GPM) 0.5 0.5
Installed cost range $1,306–$1,838 $1,309–$1,862
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

EEMAX AM005240T: 615 kWh a year Rheem SPEX55T: 609 kWh a year

EEMAX AM005240T — 615 kWh a year Rheem SPEX55T — 609 kWh a year

Rheem SPEX55T is 6 kWh a year lower than EEMAX AM005240T.

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 Rheem SPEX55T if running cost matters most: it uses 6 kWh less a year on the same test.
  • Pick the EEMAX AM005240T if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the Rheem SPEX55T.
  • Neither if you need more than 0.5 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.

Each model on its own