Mizudo FDG-CS100
Mizudo FDG-CS100 is in the DOE listing as of Oct 26, 2026.
It has a certified UEF of 0.81 and a certified flow of 2.4–2.5 gal/min at a 67°F rise.
- Gas tankless water heater
- 2 listed models
Not listed as ENERGY STAR certified on Oct 26, 2026.
Certified figures
- Flow at a 67°F rise
- 2.4–2.5gallons per minute
- UEF
- 0.81Uniform energy factor
The 2 listed models differ. A range runs from the lowest figure to the highest.
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 2.3 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 number | UEF | Flow at a 67°F rise (gal/min) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|
| FDG-CS100W-LP | 0.81 | 2.5 | 82% | Low |
| FDG-CS100W-NG | 0.81 | 2.4 | 81% | Low |
UEF is the uniform energy factor. A dash means the model has no such figure.
Its flow at a 67°F rise is 2.4 to 2.5 gallons per minute, by model number. The gas tankless type has a median flow of 4.8 gallons per minute. Its flow at a 67°F rise trails 476 of the 487 gas tankless models.
As of Oct 26, 2026, it was not listed as ENERGY STAR certified. In tests, 81% of the energy it uses ends up as hot water (UEF 0.81). In the test, daily hot water use was set to low (its draw pattern). Of 9 gas tankless models with the same draw pattern, 5 have a higher UEF. A UEF of 0.82 is the median for its type and draw pattern.
Its 2 model numbers are FDG-CS100W-LP and FDG-CS100W-NG. All of its test figures are shared by one other basic model. That one carries the ORBEK brand name.
Also listed as
They carry every figure in the table above.
- Every Mizudo basic model
- Every gas tankless water heater certified below 4.0 gallons per minute
- Every gas tankless water heater
- The most-searched gas tankless models side by side
Not covered
- Advertised figures. We have none on file for this model.