Noritz EZ98DV (GQ-C2859WX-FF US)

The 176 therms figure is computed by this site. It is not taken from the registry. It combines the registry'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. The registry lists this model's UEF as 0.96, measured under that federal test. The annual figure therefore describes the unit at the test's daily draw, not a specific household's use. It does not describe a home that draws a different amount of hot water each day. The registry source is the DOE CCD, retrieved 2026-09-19. The steps behind the energy and cost figures 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. The 176 therms figure applies to that kind of use. The registry also lists a maximum flow rate in gallons per minute of 5.3. The data here does not state the inlet water temperature behind that rate, so that detail is not available. The class is the 397 models registered as a gas tankless unit at the high draw pattern. Within it, this model is in the lowest quarter for energy use. This comparison does not describe a home whose daily use is closer to a lower draw pattern. You can compare other units in the water heater selector by fuel, space and size.

This page gives no running cost in the text. The cost of 176 therms of natural gas a year depends on your state's average residential gas price. For that reason, the page computes it from your ZIP. You can enter your ZIP in the cost calculator on your own ZIP. The 6 therms gap below the class median becomes a cost difference only at your rate, so no fixed figure is available here. The installed-cost range sits in its own block, with its source and date. It is a modeled installed-cost range, not a quote. If you are checking this unit against a heater already in place, you can find a same-class replacement by model number.