A. O. Smith GCFL-40 1** vs Friedrich PROG40S-36N RH67 PV: which uses less energy?
An asterisk in a model number stands for any character: one filing covers several variants.
At the medium draw pattern the A. O. Smith GCFL-40 1** uses 168 therms a year and the Friedrich 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.
| Figure | A. O. Smith GCFL-40 1** | Friedrich PROG40S-36N RH67 PV |
|---|---|---|
| UEF (Uniform Energy Factor) | 0.66 (better) | 0.65 |
| Energy use per year (therms) | 168 (better) | 171 |
| First hour rating (gal) | 65 | 66 |
| Rated storage volume (gal) | 38 | 39 |
| Installed cost range NLR REMDB | $1,760–$3,064 | $1,716–$2,950 |
| CPSC recall naming it CPSC | none on file | none on file |
DOE CCD · 2026-09-19 NLR REMDB · 2026-04-01 CPSC · 2026-09-24
What it costs to run
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 above.
- No CPSC recall on file names either model (list checked 2026-09-24).
- The actual warranty term is printed in each model’s documentation, not in any registry.
Which should you pick?
- Pick the A. O. Smith GCFL-40 1** if running cost matters most: it uses 3 therms less a year on the same test.
- Pick the Friedrich 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
- A. O. Smith GCFL-40 1** 168 therms a year
- Friedrich PROG40S-36N RH67 PV 171 therms a year