DoesTheMath

AMERICAN STANDARD WATER HEATERS GN40T2-3-* vs Lennox WHGS040T40PAXS****: which uses less energy?

At the medium draw pattern the AMERICAN STANDARD WATER HEATERS GN40T2-3-* and the Lennox WHGS040T40PAXS**** use the same energy, 185 therms a year each, on the same federal test. Both are filed as a gas tank, so the comparison holds; what separates them is below. Enter your ZIP to price either one on your own rate.

Side by side

Compared within one class only: models filed as a gas tank at the medium draw pattern.

Filed and computed figures
AMERICAN STANDARD WATER HEATERS GN40T2-3-* Lennox WHGS040T40PAXS****
UEF (Uniform Energy Factor) 0.6 0.6
Energy use per year (therms) 185 185
First hour rating (gal) 73 74
Rated storage volume (gal) 38 38
Installed cost range $1,410–$2,162 $1,410–$2,162
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

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 AMERICAN STANDARD WATER HEATERS GN40T2-3-* if its price or availability suits you — on energy the two are level.
  • Pick the Lennox WHGS040T40PAXS**** if you need more hot water in your busiest hour: it lists a first hour rating of 74 gallons against 73.
  • Neither if your household's busiest hour needs more than 74 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.

Each model on its own

Other comparisons

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