A. O. Smith ENJB-40 1**
A. O. Smith ENJB-40 1** is in the DOE listing as of Oct 26, 2026.
It has a labeled size of 38 gallons, a certified storage volume of 35 gallons, a certified UEF of 0.94, and a certified first-hour rating of 57 gallons of hot water.
Its advertised UEF of 0.95 from A. O. Smith differs from the certified 0.94 (Read Oct 4, 2026).
- Electric storage water heater
- 2 listed models
ENERGY STAR certification does not cover this type of water heater.
Certified figures
- Storage volume
- 35gallons
- UEF
- 0.94Uniform energy factor
- First-hour rating
- 57gallonsHot water in the first hour
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Change your hourAdvertised and certified figures
| Figure | Advertised | Certified | Advertiser | Read |
|---|---|---|---|---|
| Size | 38 gal, nominal size | 35 gal storage volume | A. O. Smith | Read Oct 4, 2026 |
| Size | 35 gal | 35 gal storage volume | A. O. Smith | Read Oct 4, 2026 |
| UEF | 0.95 | 0.94 | A. O. Smith | Read Oct 4, 2026 |
| UEF | 0.94 | 0.94 | A. O. Smith | Read Oct 4, 2026 |
| First-hour rating | 57 gal | 57 gal | A. O. Smith | Read Oct 4, 2026 |
| First-hour rating | 46 gal | 57 gal | A. O. Smith | Read Oct 4, 2026 |
Certified figures by listed model
| Model number | Storage volume (gal) | UEF | First-hour rating (gal) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|---|
| E6-40J45DVB 1** | 35 | 0.94 | 57 | 98% | Medium |
| ENJB-40 1** | 35 | 0.94 | 57 | 98% | Medium |
UEF is the uniform energy factor. A dash means the model has no such figure.
It holds 35 gallons in the test, 3 gallons less than its 38-gallon sold size. Starting full, it gives 57 gallons of hot water in its first hour of use. Reheating lets it give 22 gallons beyond the 35 gallons in its tank. In the first hour, 177 of the 477 electric storage models give more hot water. The median electric storage model gives 55 gallons in the first hour of the test.
In tests, 94% of the energy it uses ends up as hot water (UEF 0.94). The daily hot water use in the test, called its draw pattern, was medium. Its UEF is lower than that of 4 of the 297 electric storage models with its draw pattern. On its draw pattern, the median electric storage UEF is 0.92. Of the energy spent to reheat water, 98% goes into it (its recovery efficiency).
It is the basic model for E6-40J45DVB 1** and ENJB-40 1**. There are 4 more basic models with the same test figures. They are listed under 4 other brands, one each.
Also listed as
They carry every figure in the table above.
- Every A. O. Smith basic model
- Every 40-gallon electric storage water heater
- Every electric storage water heater
Not covered
- Changes to an advertised figure after the date beside it.