Natural gas water heaters (storage tank)
Tank-style gas heaters — the default replacement in a gas house.
Data current as of July 18, 2026 · 1,011 certified units · source AHRI + ENERGY STAR + DOE CCMS
Highest UEF in this group
A. O. SMITH GC9-PS4050NV 1**
UEF 0.90 · 40 gal · $245 a year to run.
See installed costs →UEF (Uniform Energy Factor) is the DOE test rating — hot water delivered per unit of fuel or electricity, measured the same way across every fuel, so it is the one number that compares a gas tank to a heat pump.
The 20 highest-UEF of 1,011 certified units · 7 with a verified place to buy
| Brand & model | UEF | Capacity | Fuel | Annual cost | Buy |
|---|---|---|---|---|---|
| A. O. SMITH GC9-PS4050NV 1** | 0.90 | 40 gal | Gas storage | $245 | Get quotes |
| A. O. SMITH GC9-PS5065NV 1** | 0.90 | 50 gal | Gas storage | $245 | Get quotes |
| RICHMOND 9GUH40-50FN | 0.90 | 40 gal | Gas storage | $245 | Get quotes |
| RHEEM XG40T09UHN50U0 | 0.90 | 40 gal | Gas storage | $245 | Buy |
| RHEEM PRO+G40-50U RH HE EC1 | 0.90 | 40 gal | Gas storage | $245 | Buy |
| RHEEM ECE G40-50U CN HE* | 0.90 | 40 gal | Gas storage | $245 | Buy |
| RHEEM XG40S12UHN50* | 0.90 | 40 gal | Gas storage | $245 | Buy |
| Envirosense Reliance Home Comfort ENV-50N-RHC 1** | 0.90 | 50 gal | Gas storage | $245 | Get quotes |
| Envirosense Enercare ENV-50N-ENER 1** | 0.90 | 50 gal | Gas storage | $245 | Get quotes |
| Envirosense ENV-50N 1** | 0.90 | 50 gal | Gas storage | $245 | Get quotes |
| Envirosense Reliance Home Comfort ENV-40N-RHC 1** | 0.90 | 40 gal | Gas storage | $245 | Get quotes |
| Envirosense Enercare ENV-40N-ENER 1** | 0.90 | 40 gal | Gas storage | $245 | Get quotes |
| Envirosense ENV-40N 1** | 0.90 | 40 gal | Gas storage | $245 | Get quotes |
| FRIEDRICH 12PROG 50-100U FD HE EC3 | 0.89 | 50 gal | Gas storage | $248 | Get quotes |
| FRIEDRICH 12PROG 50-76U FD HE EC3 | 0.89 | 50 gal | Gas storage | $248 | Get quotes |
| RHEEM ECE G50-76U CN HE | 0.89 | 50 gal | Gas storage | $248 | Buy |
| RICHMOND 6CG50-76U CR HE | 0.89 | 50 gal | Gas storage | $248 | Get quotes |
| RUUD PROU G50-76U CD HE | 0.89 | 50 gal | Gas storage | $248 | Get quotes |
| RHEEM PROP G50-76U CN HE | 0.89 | 50 gal | Gas storage | $248 | Buy |
| RHEEM ECE G50-100U CN HE EC3 | 0.89 | 50 gal | Gas storage | $248 | Buy |
Showing the top 20 by UEF. All 1,011 certified units in this group are filterable in the full database — we rank here rather than dump, because a table nobody can read is not a resource.
UEF and capacity are certified values from AHRI / ENERGY STAR / DOE CCMS; annual running cost is computed by us from national energy prices — see methodology. A tankless unit is rated on flow (GPM) rather than gallons, because it stores nothing.