LOCHINVAR T-H3J-OS-N 1**

The figure of 178 therms is calculated 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 fuel is natural gas, and the source is DOE CCD, retrieved 2026-09-19. The figure describes the federal test's draw only. A household that uses more or less hot water than the test assumes will use a different amount of gas, and the data here does not say by how much. The maximum flow rate in gallons per minute is 4.7. It is a separate rating and does not enter the annual energy calculation.

This model is compared with the 397 models registered as a gas tankless unit at the high draw pattern. Its rank is 45th lowest energy use of 397, which places it in the lowest quarter of its class. The class median is 182 therms, and this unit sits 4 therms below it, at the federal test's draw. The rating suits a larger household, because that is the usage the high draw pattern represents. It says little about a household with much lighter or heavier use, and this page has no data for those cases. To compare it with other units of the same class, use the same-class replacement search by model number or the water heater selector by fuel, space and size.

Running cost is not written in this text because it depends on your own state's average residential gas price. The annual energy of 178 therms is the quantity that price is applied to, at the high draw pattern and no other. The cost calculator on your own ZIP applies your local rate to that figure. The steps behind it are described in the annual cost methodology. The installed price appears in its own block on the page, with its source and date, and is not restated here. Measured use in a specific home is not available in the registry data, so a real bill can differ from the 178 therms shown.