Mizudo FDG-CS80
Mizudo FDG-CS80 is in the DOE listing as of Oct 26, 2026.
It has a certified UEF of 0.81 and a certified flow of 1.9–2.1 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
- 1.9–2.1gallons 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
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 1.8 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-CS80W-LP | 0.81 | 2.1 | 82% | Low |
| FDG-CS80W-NG | 0.81 | 1.9 | 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 1.9 to 2.1 gallons per minute, by model number. The median flow among gas tankless models is 4.8 gallons per minute. Its flow at a 67°F rise trails 482 of the 487 gas tankless models.
It was not listed as ENERGY STAR certified on Oct 26, 2026. In the test, 19% of its energy does not reach the hot water (UEF 0.81). Its test simulated a day of low hot water use (its draw pattern). Its UEF is lower than that of 5 of the 9 gas tankless models with its draw pattern. A UEF of 0.82 is the median for its type and draw pattern.
It is sold as FDG-CS80W-LP and FDG-CS80W-NG. Its test figures match those of 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.