A. O. Smith ENLB-50W 1**
A. O. Smith ENLB-50W 1** is in the DOE listing as of Oct 26, 2026.
It has a labeled size of 48 gallons, a certified storage volume of 44 gallons, a certified UEF of 0.91, and a certified first-hour rating of 40 gallons of hot water.
Its advertised UEF of 0.91 from A. O. Smith matches the certified 0.91 (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
- 44gallons
- UEF
- 0.91Uniform energy factor
- First-hour rating
- 40gallonsHot water in the first hour
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| Figure | Advertised | Certified | Advertiser | Read |
|---|---|---|---|---|
| Size | 48 gal, nominal size | 44 gal storage volume | A. O. Smith | Read Oct 4, 2026 |
| Size | 44 gal | 44 gal storage volume | A. O. Smith | Read Oct 4, 2026 |
| UEF | 0.91 | 0.91 | A. O. Smith | Read Oct 4, 2026 |
| First-hour rating | 40 gal | 40 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 |
|---|---|---|---|---|---|
| ENLB-50W 1** | 44 | 0.91 | 40 | 98% | Low |
| PNLB-50W 1** | 44 | 0.91 | 40 | 98% | Low |
UEF is the uniform energy factor. A dash means the model has no such figure.
It holds 44 gallons in the test, 4 gallons less than its 48-gallon sold size. Over one hour from a full tank, it gave 40 gallons in the test (its first-hour rating). Of 477 electric storage models, 444 give more hot water in the first hour. The median electric storage model gives 55 gallons in the first hour of the test.
In tests, 91% of the energy it uses ends up as hot water (UEF 0.91). Its test simulated a day of low hot water use (its draw pattern). Its UEF is lower than that of 81 of the 157 electric storage models with its draw pattern. For its type and draw pattern, the UEF runs from 0.88 to 0.95. The water took in 98% of the energy used to reheat it (its recovery efficiency).
It is sold as ENLB-50W 1** and PNLB-50W 1**. Its test figures match those of 2 other basic models. The Lochinvar and State brands list one or more 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.