Ariston ENS40LUB*
Ariston ENS40LUB* is in the DOE listing as of Oct 19, 2026.
- Electric storage water heater
- 1 listed model
ENERGY STAR certification does not cover this type of water heater.
Its figures are also listed under AMERICAN STANDARD WATER HEATERS ENS40LUB*.
Certified figures
- Storage volume
- 36gallons
- UEF
- 0.92Uniform energy factor
- First-hour rating
- 50gallonsHot water in the first hour
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| Model number | Storage volume (gal) | UEF | First-hour rating (gal) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|---|
| ESB40S* | 36 | 0.92 | 50 | 98% | Low |
UEF is the uniform energy factor. A dash means the model has no such figure.
It holds 36 gallons in the test, 4 gallons less than its 40-gallon sold size. Starting full, it gives 50 gallons of hot water in its first hour of use. That is 14 gallons more than its tank holds, since it reheats during the hour. Of 477 electric storage models, 321 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, 92% of the energy went to hot water, so its UEF is 0.92. In the test, daily hot water use was set to low (its draw pattern). Of 157 electric storage models with the same draw pattern, 12 have a higher UEF and 76 a lower one. Its UEF is the median for its type and draw pattern. The water took in 98% of the energy used to reheat it (its recovery efficiency).
Its test figures match those of 2 other basic models. Those basic models are sold with AMERICAN STANDARD WATER HEATERS and Lennox as their brand names. You can find the whole group on the page for the AMERICAN STANDARD WATER HEATERS ENS40LUB*.
Also listed as
They carry every figure in the table above.
- Every Ariston basic model
- Every 40-gallon electric storage water heater
- Every electric storage water heater
Not covered
- Advertised figures. We have none on file for this model.