Ariston ENS40T-*
Ariston ENS40T-* is in the DOE listing as of Oct 26, 2026.
It has a labeled size of 40 gallons, a certified storage volume of 36 gallons, a certified UEF of 0.92, and a certified first-hour rating of 51 gallons of hot water.
- Electric storage water heater
- 2 listed models
ENERGY STAR certification does not cover this type of water heater.
Certified figures
- Storage volume
- 36gallons
- UEF
- 0.92Uniform energy factor
- First-hour rating
- 51gallonsHot water in the first hour
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Change your hourCertified figures by listed model
| Model number | Storage volume (gal) | UEF | First-hour rating (gal) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|---|
| ES40M* | 36 | 0.92 | 51 | 98% | Medium |
| LCE40M* | 36 | 0.92 | 51 | 98% | Medium |
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 51 gallons of hot water in its first hour of use. Its tank holds 36 gallons, so reheating adds 15 gallons during the first hour. Of 477 electric storage models, 286 give more hot water in the first hour. Among electric storage models, the median first-hour rating is 55 gallons.
In the test, 8% of its energy does not reach the hot water (UEF 0.92). In the test, daily hot water use was set to medium (its draw pattern). Of 297 electric storage models with the same draw pattern, 81 have a higher UEF and 2 a lower one. For its type and draw pattern, its UEF sits at the median. The water took in 98% of the energy used to reheat it (its recovery efficiency).
It is the basic model for ES40M* and LCE40M*. All of its test figures are shared by one other basic model. The brand name on that one is Lennox.
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.