Noritz NRC98DV (GQ-C2857WS-FF US)

This site computed the 186 therms figure. The registry does not publish it. It combines the model's UEF, the ratio of hot water delivered to energy used, with the DOE test's daily hot-water draw for the high draw pattern. This unit's UEF is 0.91, taken from the DOE CCD, retrieved 2026-09-19. The result describes gas use at the federal test's daily draw, not at any particular address. Use in a specific home is not available here, because it depends on that home's own hot-water draw. A plumber or seller checking a quoted figure should confirm that it refers to the high draw pattern, because this figure applies only to that pattern. The steps are set out in how the annual cost is calculated.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. This is the level of use that the 186 therms figure describes. The registry lists the unit's maximum flow rate in gallons per minute as 5.1. The data does not say whether that rate covers every fixture a given home runs at once. Its class holds 397 models registered as a gas tankless unit at the high draw pattern. Within that class, it ranks 213th lowest in energy use. That places it in the second-highest quarter of the class for energy use. A reader who needs a model below the 182 therms class median will need a different model. The selector by fuel, space and size filters models on those criteria.

The text on this page gives no running cost. That cost depends on the reader's state average residential gas price, applied to the 186 therms of natural gas at the high draw pattern. To see the figure at your own rate, enter a ZIP in the cost calculator on your own ZIP. This model uses 4 therms a year more than the 182 therms class median. What that gap costs also depends on the same rate, and it is not available here. The installed price range on this page is a modeled range, not a quote, and it has its own block with its source and date. To compare against another model registered at the same draw pattern, find a same-class replacement by model number.