Noritz NR83DVC (GQ-2457WS-FFA US)

This site calculated the 206 therms figure; the registry does not list it. It combines the registry's UEF, the ratio of hot water delivered to energy used, with the daily hot-water draw that the DOE test sets for the high draw pattern. The registry lists this model's UEF as 0.82. The source is the DOE CCD, retrieved 2026-09-19. The figure describes the unit at the test's daily draw, not in any particular home. A household that draws more hot water than the test assumes will use more gas than this figure. A household that draws less will use less. The steps behind the figure are set out on the page explaining how the annual energy and cost are calculated.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. The registry lists a maximum flow rate in gallons per minute of 4.6 for this model. Among the 397 gas tankless models registered at the high draw pattern, this unit ranks 229th from lowest energy use. That places it in the second-highest quarter of its class for energy use. For a home that matches the high pattern, models nearer the 182 therms median use less gas at the same test draw. For a smaller household, this page has no figure at a lower draw pattern; that is not available here. To list other models in the same class, use the same-class replacement search by model number.

This text does not state the running cost. It depends on the average residential gas price in the reader's state, so the page computes it from the reader's ZIP. The input is the same 206 therms a year at the high draw pattern. This unit uses 24 therms more gas a year than its class median. At any single gas rate, its running cost is therefore above that of a model at the median. The size of that gap depends on the local gas price and is not given here. Enter a ZIP in the water heater cost calculator for your ZIP to see it. The installed price range elsewhere on the page is a modeled range, not a quote.