AMERICAN T-H3S-DV-N 1**

The figure of 178 therms is computed by this site, not published by the registry. It combines the registry's UEF, the ratio of hot water delivered to energy used, of 0.95 with the DOE test's daily hot-water draw for the high draw pattern. The source is DOE CCD, retrieved 2026-09-19. The value applies only to natural gas at that test draw. A home that uses more or less hot water than the test assumes will use a different amount of gas, and measured use in a real home is not available in this data. The calculation steps are set out in how the annual cost is calculated.

The comparison group is the 397 models registered as a gas tankless unit at the high draw pattern. This model holds the 45th lowest energy use of 397, which puts it in the lowest quarter of its class. Its use is 4 therms below the class median of 182 therms. The high draw pattern describes a larger household, or one where showers and laundry overlap, so this is the group the figure fits. The registry lists a maximum flow rate in gallons per minute of 5.4. How that flow holds up at a given inlet water temperature is not in the data and is unknown here. To compare other fuels or sizes, use the water heater selector by fuel, space and size.

The figure is less representative for a household whose hot-water demand differs from the high draw pattern, because the test draw would then over- or understate its use. The energy for that household is not available from this registry data. Running cost is not stated in the text, since it depends on your state's average residential gas price. The cost calculator on your own ZIP applies that price to the 178 therms shown for T-H3S-DV-N 1**. If you need a unit in the same class, find a same-class replacement by model number. The installed price range on this page sits in its own block with its source and date, and it is a modeled range, not a quote.