Mizudo HW180
Mizudo HW180 is in the DOE listing as of Oct 19, 2026.
- Gas tankless water heater
- 2 listed models
Not listed as ENERGY STAR certified on Oct 19, 2026.
Its figures are also listed under Fogatti FDG-PM180S.
Certified figures
- Flow at a 67°F rise
- 4.5gallons per minute
- UEF
- 0.81–0.82Uniform 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
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 4.3 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 |
|---|---|---|---|---|
| HW180A0W-LP | 0.82 | 4.5 | 82% | High |
| HW180A0W-NG | 0.81 | 4.5 | 81% | High |
UEF is the uniform energy factor. A dash means the model has no such figure.
It heats 4.5 gallons per minute of water by 67°F in the test. The median flow among gas tankless models is 4.8 gallons per minute. Among 487 gas tankless models, 319 give more flow at a 67°F rise.
On Oct 19, 2026, this heater was not listed as ENERGY STAR certified. Its listed models turn 81 to 82% of the energy used into hot water (UEF 0.81 to 0.82). Its test ran at the high level of daily hot water use. Its UEF is lower than that of 243 of the 399 gas tankless models with its draw pattern. For its type and draw pattern, the median UEF is 0.93.
It is the basic model for HW180A0W-LP and HW180A0W-NG. There are 3 more basic models with the same test figures. The Fogatti and Westinghouse brands list one or more of them. For the full group, see the Fogatti FDG-PM180S page.
It may qualify for one rebate program if it meets their other terms.
Also listed as
They carry every figure in the table above.
Rebates
| Program | State | Status | Program page |
|---|---|---|---|
| SoCalGas High-Efficiency or ENERGY STAR Certified Natural Gas Tankless Water Heaters rebate | CA | May qualify if it meets the other terms | Its own page |
Programs change their terms. Check the program's own page before you buy.
- Every Mizudo basic model
- Every gas tankless water heater certified at 4.0 to 4.9 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.