DoesTheMath

Lennox WHGS040S37NAXE**** vs Rheem PROG40-36N RH62 MH DVX: which uses less energy?

At the medium draw pattern the Lennox WHGS040S37NAXE**** and the Rheem PROG40-36N RH62 MH DVX 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
Lennox WHGS040S37NAXE**** Rheem PROG40-36N RH62 MH DVX
UEF (Uniform Energy Factor) 0.6 0.6
Energy use per year (therms) 185 185
First hour rating (gal) 64 63
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 Lennox WHGS040S37NAXE**** if its price or availability suits you — on energy the two are level.
  • Pick the Rheem PROG40-36N RH62 MH DVX if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the Lennox WHGS040S37NAXE****.
  • Neither if your household's busiest hour needs more than 64 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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