A. O. SMITH G6N-UT4040NVR 5** vs Rheem XG40T12HE40U0: which uses less energy?
At the high draw pattern the Rheem XG40T12HE40U0 uses 260 therms a year and the A. O. SMITH G6N-UT4040NVR 5** 264 — 4 therms (2%) less, about 41 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 high draw pattern.
| Figure | A. O. SMITH G6N-UT4040NVR 5** | Rheem XG40T12HE40U0 |
|---|---|---|
| UEF (Uniform Energy Factor) | 0.64 | 0.65 (better) |
| Energy use per year (therms) | 264 | 260 (better) |
| First hour rating (gal) | 83 | 84 |
| Rated storage volume (gal) | 38 | 38 |
| Installed cost range | $1,643–$2,763 | $1,702–$2,914 |
| ENERGY STAR certified | not matched | not matched |
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 below.
- The actual warranty term is printed in each model’s documentation, not in any registry.
Which should you pick?
- Pick the Rheem XG40T12HE40U0 if running cost matters most: it uses 4 therms less a year on the same test.
- Pick the A. O. SMITH G6N-UT4040NVR 5** if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the Rheem XG40T12HE40U0.
- Neither if your household's busiest hour needs more than 84 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.
Each model on its own
-
A. O. SMITH G6N-UT4040NVR 5**
Its filed figures, class position and running cost on your ZIP.
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Rheem XG40T12HE40U0
Its filed figures, class position and running cost on your ZIP.