Ruud SCG40T03ST34U1

The 188 therms figure does not appear in the registry itself. This site computed it from the registry's UEF, the ratio of hot water delivered to energy used. The second input is the DOE test's daily hot-water draw for the medium draw pattern. For this model the UEF is 0.59, from the DOE CCD as retrieved on 2026-09-19. The result holds only at that test draw. If your household draws more or less hot water than the test assumes, your yearly gas use will differ from 188 therms. This page does not know your actual use, so read the figure as a test-condition value. The page on how the annual cost is calculated lists each step of the computation.

The medium draw pattern stands for the typical household size DOE assigns to that test profile. The 188 therms figure applies most closely where daily hot-water use is near that profile. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 67 gallons. The tank's rated volume is 38 gallons. A plumber or seller can check both values, and the UEF of 0.59, against the registry listing for SCG40T03ST34U1. A household whose busy mornings run well past the medium profile falls outside the condition behind these figures. For that case, the selector by fuel, space and size narrows the registered models on those three inputs.

Among the 288 models registered as a gas tank at the medium draw pattern, this one ranks 186th lowest for energy use. That places it in the second-highest quarter of its class for energy use, 3 therms above the 185 therms class median. A reader looking for a unit below that median can find a same-class replacement by model number. The running cost is not given in this text. It depends on your state's average residential gas price, which this page does not know in advance. The cost calculator on your own ZIP applies that price to 188 therms at the medium draw pattern. The modeled installed-cost range appears in its own block, with its source and date; it is not a quote.