A. O. Smith ENS-50 1**
A. O. Smith ENS-50 1** is in the DOE listing as of Oct 26, 2026.
It has a labeled size of 50 gallons, a certified storage volume of 46 gallons, a certified UEF of 0.92, 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 0.92 (Read Oct 5, 2026).
- Electric storage water heater
- 6 listed models
ENERGY STAR certification does not cover this type of water heater.
Certified figures
- Storage volume
- 46gallons
- UEF
- 0.92Uniform energy factor
- First-hour rating
- 57gallonsHot water in the first hour
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| Figure | Advertised | Certified | Advertiser | Read |
|---|---|---|---|---|
| Size | 50 gal, nominal size | 46 gal storage volume | A. O. Smith | Read Oct 5, 2026 |
| Size | 50 gal, nominal size | 46 gal storage volume | Lowe's | Archived copy, Oct 1, 2024 |
| Size | 46 gal | 46 gal storage volume | A. O. Smith | Read Oct 5, 2026 |
| UEF | 0.95 | 0.92 | A. O. Smith | Read Oct 5, 2026 |
| UEF | 0.92 | 0.92 | A. O. Smith | Read Oct 5, 2026 |
| UEF | 0.92 | 0.92 | Lowe's | Archived copy, Oct 1, 2024 |
| First-hour rating | 57 gal | 57 gal | A. O. Smith | Read Oct 5, 2026 |
| First-hour rating | 57 gal | 57 gal | Lowe's | Archived copy, Oct 1, 2024 |
Certified figures by listed model
| Model number | Storage volume (gal) | UEF | First-hour rating (gal) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|---|
| E6-50R38D 1** | 46 | 0.92 | 57 | 98% | Medium |
| E6-50R45D 1** | 46 | 0.92 | 57 | 98% | Medium |
| E6-50R45DV 1** | 46 | 0.92 | 57 | 98% | Medium |
| ENS-50 1** | 46 | 0.92 | 57 | 98% | Medium |
| HNS-50 1** | 46 | 0.92 | 57 | 98% | Medium |
| PNS-50 1** | 46 | 0.92 | 57 | 98% | Medium |
UEF is the uniform energy factor. A dash means the model has no such figure.
It holds 46 gallons in the test, 4 gallons less than its 50-gallon sold size. It delivers 57 gallons of hot water in the test's first hour. Its tank holds 46 gallons, so reheating adds 11 gallons during the first hour. In the first hour, 177 of the 477 electric storage models give more hot water. Among electric storage models, the median first-hour rating is 55 gallons.
In tests, 92% of the energy went to hot water, so its UEF is 0.92. Its test simulated a day of medium hot water use (its draw pattern). Among 297 electric storage models on its draw pattern, 81 have a higher UEF. Its UEF is the median for its type and draw pattern. When it reheats water in the test, 98% of the energy it uses ends up in the water.
It is sold under 6 model numbers in all. Its test figures match those of 5 other basic models. Each of the 5 other brands lists one of them.
Also listed as
They carry every figure in the table above.
- Every A. O. Smith basic model
- Every 50-gallon electric storage water heater
- Every electric storage water heater
Not covered
- Changes to an advertised figure after the date beside it.