JOHN WOOD GCFL-50 1**

This site calculated the 245 therms figure; the registry does not publish it. The calculation uses the model's UEF, the ratio of hot water delivered to energy used, which is 0.69. It also uses the DOE test's daily hot-water draw for the high draw pattern. The rating comes from the DOE Compliance Certification Database, retrieved 2026-09-19. On that basis the model ranks 130th for lowest energy use among the 414 models in its class. That puts it in the second-lowest quarter of its class. The figure applies only at the test's daily draw. A household using a different amount of hot water will use a different amount of gas. The page on how the annual cost is calculated sets out the steps this page follows.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. For that use, the model lists a first hour rating, the gallons of hot water available in the first hour from a full tank. Its first hour rating is 78 gallons, from a rated volume of 49 gallons. The registry data does not cover a home whose busiest hour needs more than 78 gallons. The 245 therms figure also does not describe a smaller household, because the figure is tied to the high draw pattern. This page has no energy figure for this model at a lower draw pattern, so that value is not available. To compare other sizes or fuels, use the water heater selector by fuel, space and size.

This text does not give a running cost because it depends on your state's average residential gas price. The page calculates it from your ZIP code by applying that price to the 245 therms of natural gas a year. The cost value of the 15 therms gap to the 260 therms class median also depends on your price. The installed-cost range appears in its own block on this page, with its source and date. It is a modeled range, not a quote. For a figure based on your own rate, use the cost calculator for your ZIP. To match this unit with another model in the same class, find a same-class replacement by model number.