DoesTheMath

ECOSENSE RHE40SP vs Ruud PROG39S-38U RH62 EC1*: which uses less energy?

At the medium draw pattern the ECOSENSE RHE40SP uses 148 therms a year and the Ruud PROG39S-38U RH62 EC1* 188 — 40 therms (21%) less, about 401 therms over ten years. Both are filed as a gas tank, so the comparison holds. Enter your ZIP below to price the difference.


Side by side

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

Filed and computed figures
Figure ECOSENSE RHE40SP Ruud PROG39S-38U RH62 EC1*
UEF (Uniform Energy Factor) 0.75 (better) 0.59
Energy use per year (therms) 148 (better) 188
First hour rating (gal) 68 68
Rated storage volume (gal) 37 37
Installed cost range not published not published
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

ECOSENSE RHE40SP: 148 therms a year Ruud PROG39S-38U RH62 EC1*: 188 therms a year

ECOSENSE RHE40SP — 148 therms a year Ruud PROG39S-38U RH62 EC1* — 188 therms a year

ECOSENSE RHE40SP is 40 therms a year lower than Ruud PROG39S-38U RH62 EC1*.

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 ECOSENSE RHE40SP if running cost matters most: it uses 40 therms less a year on the same test.
  • Pick the Ruud PROG39S-38U RH62 EC1* if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the ECOSENSE RHE40SP.
  • Neither if your household's busiest hour needs more than 68 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.

Each model on its own