MRCOOL MTWH04540E
MRCOOL MTWH04540E 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 A. O. Smith ENS-40 1**.
Certified figures
- Storage volume
- 37gallons
- UEF
- 0.92Uniform energy factor
- First-hour rating
- 55gallonsHot 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 |
|---|---|---|---|---|---|
| MTWH04540E | 37 | 0.92 | 55 | 98% | Medium |
UEF is the uniform energy factor. A dash means the model has no such figure.
Over one hour from a full tank, it gave 55 gallons in the test (its first-hour rating). That is 18 gallons more than its tank holds, since it reheats during the hour. In the first hour, 204 of the 477 electric storage models give more hot water. The median electric storage model gives the same amount in its first hour.
In tests, 92% of the energy it uses ends up as hot water (UEF 0.92). Its test ran at the medium level of daily hot water use. Of 297 electric storage models with the same draw pattern, 81 have a higher UEF. 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).
There are 14 more basic models with the same test figures. In all, 7 other brands list one or more of them. You can find the whole group on the page for the A. O. Smith ENS-40 1**.
Also listed as
They carry every figure in the table above.
- A. O. Smith ENS-40 1**
- American ENS-40 1**
- Lochinvar ENS-40 1**
- Midea D40-45FH
- Midea D40-45FJ
- Midea MEWH40S82S1
- Midea MEWH40T82S1
- MRCOOL MEWH40S82S1
- MRCOOL MEWH40T82S1
- MRCOOL MTWH04540ET
- RELIANCE WATER HEATERS ENS-40 1**
- State ENS-40 1**
2 more basic models carry these figures.
Not covered
- Advertised figures. We have none on file for this model.