Rheem RTEX-13
Rheem RTEX-13 is in the DOE listing as of Oct 26, 2026.
It has a certified UEF of 0.88 and a certified flow of 1.3 gal/min at a 67°F rise.
Its certified flow is 1.3 gal/min at a 67°F rise, while Rheem advertises 3.17 gal/min, no rise stated (Read Oct 4, 2026), so a comparison at the same rise is not possible.
- Electric tankless water heater
- 5 listed models
ENERGY STAR certification does not cover this type of water heater.
Certified and advertised figures
- Flow at a 67°F rise
- 1.3gallons per minuteCertified
- Advertised flow
- 3.17gallons per minuteRheem, no rise stated
- UEF
- 0.88Uniform energy factor
Your fixtures at once
Change your hour and flowFlow where you live
The heater gives less flow when colder incoming water needs a bigger rise.
- 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 1.2 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 | up to 0.96 | 0.88 | Rheem | Read Oct 4, 2026 |
| Flow | 3.17 gal/min, no rise stated | 1.3 gal/min at a 67°F rise | Rheem | Read Oct 4, 2026 |
| Flow | up to 2.3 gal/min, no rise stated | 1.3 gal/min at a 67°F rise | Rheem | Read Oct 4, 2026 |
| Flow | up to 2.54 gal/min, no rise stated | 1.3 gal/min at a 67°F rise | The Home Depot | Archived copy, Aug 19, 2024 |
Certified figures by listed model
| Model number | UEF | Flow at a 67°F rise (gal/min) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|
| EEM24013 | 0.88 | 1.3 | 98% | — |
| HA013240 | 0.88 | 1.3 | 98% | — |
| RETEX-13 | 0.88 | 1.3 | 98% | — |
| RMTEX-13 | 0.88 | 1.3 | 98% | — |
| RTEX-13 | 0.88 | 1.3 | 98% | — |
UEF is the uniform energy factor. A dash means the model has no such figure.
At a 67°F rise, its flow in the test is 1.3 gallons per minute. The electric tankless type has a median flow of 0.7 gallons per minute. Among 337 electric tankless models, 56 give more flow at a 67°F rise.
In tests, 88% of the energy it uses ends up as hot water (UEF 0.88). When it runs, 98% of the energy it uses reaches the water (its recovery efficiency).
All 5 of its model numbers carry the same certified figures. All of its test figures are shared by one other basic model. That one carries the EEMAX brand name.
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.