MRCOOL MTWH04540ET
MRCOOL MTWH04540ET 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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| Model number | Storage volume (gal) | UEF | First-hour rating (gal) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|---|
| MTWH04540ET | 37 | 0.92 | 55 | 98% | Medium |
UEF is the uniform energy factor. A dash means the model has no such figure.
It delivers 55 gallons of hot water in the test's first hour. Its tank holds 37 gallons, so reheating adds 18 gallons during the first hour. Of 477 electric storage models, 204 give more hot water in the first hour. In first-hour rating, it ties the median electric storage model.
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). Among 297 electric storage models on its draw pattern, 81 have a higher UEF. For its type and draw pattern, its UEF sits at the median. Of the energy spent to reheat water, 98% goes into it (its recovery efficiency).
All of its test figures are shared by 14 other basic models. Besides this brand, 7 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 MTWH04540E
- 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.