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Rheem AM004120T

Rheem AM004120T is in the DOE listing as of Oct 26, 2026.

It has a certified UEF of 0.94 and a certified flow of 0.3 gal/min at a 67°F rise.

  • Electric tankless water heater
  • 1 listed model

ENERGY STAR certification does not cover this type of water heater.

Flow at a 67°F rise
0.3gallons per minute
UEF
0.94Uniform energy factor
See it among every electric tankless model

Flow where you live

Colder incoming water needs a bigger rise, so the heater gives 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 0.3 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.

Certified figures by listed model

Model numberUEFFlow at a 67°F rise (gal/min)Recovery efficiencyDraw pattern
RTEH004120MV0.940.393%Very small

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 0.3 gallons per minute. The electric tankless type has a median flow of 0.7 gallons per minute. Among 337 electric tankless models, 271 give more flow at a 67°F rise.

In tests, 94% of the energy went to hot water, so its UEF is 0.94. Its test simulated a day of very small hot water use (its draw pattern). Of 272 electric tankless models with the same draw pattern, 187 have a higher UEF. A UEF of 0.96 is the median for its type and draw pattern. Of the energy it spends heating water, 93% ends up in it (its recovery efficiency).

Updated Oct 26, 2026 · Methodology

Not covered

  • Advertised figures. We have none on file for this model.