DoesTheMath

Ruud PROG40S-36N RH67 PV vs STATE GCFL-40 1**: which uses less energy?

At the medium draw pattern the STATE GCFL-40 1** uses 168 therms a year and the Ruud PROG40S-36N RH67 PV 171 — 3 therms (2%) less, about 26 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 Ruud PROG40S-36N RH67 PV STATE GCFL-40 1**
UEF (Uniform Energy Factor) 0.65 0.66 (better)
Energy use per year (therms) 171 168 (better)
First hour rating (gal) 66 65
Rated storage volume (gal) 39 38
Installed cost range $1,716–$2,950 $1,760–$3,064
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

Ruud PROG40S-36N RH67 PV: 171 therms a year STATE GCFL-40 1**: 168 therms a year

Ruud PROG40S-36N RH67 PV — 171 therms a year STATE GCFL-40 1** — 168 therms a year

STATE GCFL-40 1** is 3 therms a year lower than Ruud PROG40S-36N RH67 PV.

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 STATE GCFL-40 1** if running cost matters most: it uses 3 therms less a year on the same test.
  • Pick the Ruud PROG40S-36N RH67 PV if you need more hot water in your busiest hour: it lists a first hour rating of 66 gallons against 65.
  • Neither if your household's busiest hour needs more than 66 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.

Each model on its own