STATE TK-110U-E 2**

This site computed the 137 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 DOE test's daily hot-water draw for the medium pattern. This model's UEF is 0.81. The inputs come from the DOE Compliance Certification Database, retrieved 2026-09-19. The result applies only at the federal test's daily draw. A household that uses more or less hot water than that draw will use a different amount of gas. This page does not know that amount. The steps are set out in how the annual energy and cost figures are calculated.

The class has 80 models registered as a gas tankless unit at the medium draw pattern. This model ranks 52nd lowest for annual energy use among them. That places it in the second-highest quarter of its class for energy use, 2 therms above the class median. The medium pattern stands for the daily hot-water use of a typical household on the federal test. The registry lists a maximum flow rate in gallons per minute of 3.5 for this unit. Check that figure against the fixtures that run at the same time. If you want lower annual energy use at the same draw pattern, you can find same-class replacements by model number.

This text gives no running cost. The cost of 137 therms a year depends on your state's average residential gas price, so the page calculates it from your ZIP. You can enter it in the water heater cost calculator for your own ZIP. At any single gas price, the 2 therms gap above the class median changes the cost in the same direction. The installed-price range appears in its own block with its source and date. It is a modeled range, not a quote. Neither figure reflects a household whose hot-water use differs from the medium draw pattern. To compare other fuels, spaces or sizes, use the water heater selector by fuel, space and size.