Mizudo HW180

The 206 therms figure does not come from the registry itself. This site calculated it from DOE inputs. The model's input is its UEF, the ratio of hot water delivered to energy used. The registry lists the UEF of the Mizudo HW180 as 0.82. The other input is the federal test's daily hot-water draw for the high pattern. The source is the DOE CCD, retrieved 2026-09-19. This model is compared with the 397 models registered as a gas tankless unit at the high draw pattern. Within that class, this model ranks 229th lowest for energy use. That puts it in the second-highest quarter of its class for energy use.

The high draw pattern describes a larger household, or one where showers and laundry overlap. The 206 therms figure applies only to that daily usage at the federal test's draw. The data here gives no figure for this model at a lower draw pattern, so its gas use there is not available. The registry lists its maximum flow rate in gallons per minute as 4.5. The data does not say whether that rate covers a particular home's fixtures running at the same time. To compare it with other units, use the water heater selector by fuel, space and size. If you are matching an existing unit, the same-class replacement search by model number finds models in this class.

This text gives no running cost for the Mizudo HW180. The cost of 206 therms of natural gas a year depends on the average residential gas price in your state. The page calculates it from your ZIP, and the cost calculator for your own ZIP shows the result. The gap of 24 therms above the class median also has a cost that depends on your rate. The method behind the annual cost figure explains how the rate is applied to the energy figure. The installed price range appears in its own block, with its source and date. It is a modeled installed-cost range, not a quote from an installer.