DoesTheMath

AMERICAN STANDARD WATER HEATERS ENS40LU-* vs Stiebel Eltron Accelera 220 E: which uses less energy?

At the low draw pattern the Stiebel Eltron Accelera 220 E uses 799 kWh a year and the AMERICAN STANDARD WATER HEATERS ENS40LU-* 2,466 — 1,668 kWh (68%) less, about 16,675 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
AMERICAN STANDARD WATER HEATERS ENS40LU-* Stiebel Eltron Accelera 220 E
UEF (Uniform Energy Factor) 0.91 2.81 (better)
Energy use per year (kWh) 2,466 799 (better)
First hour rating (gal) 41 41
Rated storage volume (gal) 36 58
Installed cost range not published not published
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

AMERICAN STANDARD WATER HEATERS ENS40LU-*: 2,466 kWh a year Stiebel Eltron Accelera 220 E: 799 kWh a year

AMERICAN STANDARD WATER HEATERS ENS40LU-* — 2,466 kWh a year Stiebel Eltron Accelera 220 E — 799 kWh a year

Stiebel Eltron Accelera 220 E is 1,667 kWh a year lower than AMERICAN STANDARD WATER HEATERS ENS40LU-*.

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 Stiebel Eltron Accelera 220 E if running cost matters most: it uses 1,668 kWh less a year on the same test.
  • Pick the AMERICAN STANDARD WATER HEATERS ENS40LU-* if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the Stiebel Eltron Accelera 220 E.
  • Neither if your household's busiest hour needs more than 41 gallons of hot water — neither lists more.

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.