STATE GCFL-40 1**

The registry does not list the 168 therms figure. This site calculated it from two inputs. The first is the model's UEF, the ratio of hot water delivered to energy used. The second is the daily hot-water draw that the DOE test sets for the medium draw pattern. The UEF for this model is 0.66 in the DOE Compliance Certification Database, retrieved 2026-09-19. So the figure applies only at that test draw. It does not describe a household whose daily hot-water use differs from the medium pattern. It also assumes natural gas, the fuel this model is registered for. Each step of the method, from UEF to yearly gas use, is set out in how the annual cost is calculated.

In its class, the model has the 27th lowest energy use of the 288 gas tank models tested at the medium draw pattern. That places it in the lowest quarter of the class, in addition to the gap to the median given above. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 65 gallons. Its rated volume is 38 gallons. These figures describe a household whose use matches the medium pattern. A household whose busiest hour needs more than 65 gallons is outside what the rating covers. The registry does not show how the model performs outside the test conditions. To compare other units in the same class, use the same-class replacement search by model number.

The text on this page does not give a running cost for the 168 therms a year. That cost depends on the average residential gas price in your state, which the page does not know until you enter a ZIP. The cost calculator for your own ZIP applies that state price to this model's 168 therms. The result still holds only at the medium draw pattern. The installed price range appears in a separate block with its source and date. It is a modeled range, not a quote. This data does not include future gas prices, maintenance costs or the model's service life, so those are unknown here.