Rheem ECO 11
Rheem ECO 11 is in the DOE listing as of Oct 26, 2026.
It has a certified UEF of 0.92 and a certified flow of 1.2 gal/min at a 67°F rise.
Its certified flow is 1.2 gal/min at a 67°F rise, while The Home Depot advertises 2.15 gal/min at a 35°F rise (Archived copy, May 20, 2025), so the two figures are not at the same rise.
- Electric tankless water heater
- 3 listed models
ENERGY STAR certification does not cover this type of water heater.
Certified figures
- Flow at a 67°F rise
- 1.2gallons per minute
- UEF
- 0.92Uniform energy factor
Your fixtures at once
Change your hour and flowFlow where you live
A bigger rise from colder incoming water leaves the heater with less flow.
- Cold water
- Cold water must be at least 10°F colder than the hot water setting.
- Flow estimate
- The estimate uses the lowest certified flow among the listed models. It is about 1.1 gal/min at a 70°F rise.
Flow limits
- The estimate excludes the flow needed to turn the heater on, heat lost in pipes, and installation.
- Cold water from a well or long pipe run can differ from the temperature you enter.
- Without a stated flow limit, estimates for warmer water may exceed the heater’s actual flow.
Advertised and certified figures
| Figure | Advertised | Certified | Advertiser | Read |
|---|---|---|---|---|
| UEF | 0.98 | 0.92 | The Home Depot | Archived copy, May 20, 2025 |
| Flow | 2.15 gal/min at a 35°F rise | 1.2 gal/min at a 67°F rise | The Home Depot | Archived copy, May 20, 2025 |
| Flow | 1.67 gal/min at a 45°F rise | 1.2 gal/min at a 67°F rise | The Home Depot | Archived copy, May 20, 2025 |
| Flow | 1.37 gal/min at a 55°F rise | 1.2 gal/min at a 67°F rise | The Home Depot | Archived copy, May 20, 2025 |
| Flow | 1.16 gal/min at a 65°F rise | 1.2 gal/min at a 67°F rise | The Home Depot | Archived copy, May 20, 2025 |
Certified figures by listed model
| Model number | UEF | Flow at a 67°F rise (gal/min) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|
| RETEX-11 | 0.92 | 1.2 | 92% | Very small |
| RMTEX-11 | 0.92 | 1.2 | 92% | Very small |
| RTEX-11 | 0.92 | 1.2 | 92% | Very small |
UEF is the uniform energy factor. A dash means the model has no such figure.
It warms 1.2 gallons per minute of water from 58°F to 125°F in the test. The median flow among electric tankless models is 0.7 gallons per minute. Of 337 electric tankless models, 64 have a higher flow than this one.
In tests, 92% of the energy it uses ends up as hot water (UEF 0.92). The daily hot water use in the test, called its draw pattern, was very small. Its UEF is lower than that of 249 of the 272 electric tankless models with its draw pattern. A UEF of 0.96 is the median for its type and draw pattern. Of the energy it spends heating water, 92% ends up in it (its recovery efficiency).
It is sold as RETEX-11, RMTEX-11, and RTEX-11. All of its test figures are shared by 2 other basic models. The ECOSMART and EEMAX brands list one or more of them.
Also listed as
They carry every figure in the table above.
- Every Rheem basic model
- Every electric tankless water heater certified at 1.0 to 1.9 gallons per minute
- Every electric tankless water heater
Not covered
- Changes to an advertised figure after the date beside it.