LOCHINVAR GCB-40 4**

This site computed the 264 therms figure. The registry does not list it. The first input is the registry's UEF, the ratio of hot water delivered to energy used, which is 0.64 for this model. The second input is the daily hot-water draw that the DOE test sets for the high draw pattern. Both inputs come from the DOE CCD, retrieved 2026-09-19. A household that uses more or less hot water than the test day will burn a different amount of gas. How much different is unknown, because this page has no data on real household use. The steps behind the annual figure show how the UEF and the test draw combine into 264 therms a year.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. For that use, the registry lists a first hour rating, the gallons of hot water available in the first hour from a full tank. For this model it is 78 gallons, from a rated volume of 38 gallons. The rating does not cover a home whose busiest hour needs more than 78 gallons. The 264 therms figure applies only at the high pattern. This page has no figure for a lighter pattern, so the energy use of a smaller household is not available here. To compare other gas tanks, use the selector by fuel, space and size.

The 4 therms gap to the class median, noted above, places this model in the second-highest quarter of its class for energy use. That position reflects energy use at the test's daily draw only. It does not reflect the cost at any address. The running cost is not given in this text. It depends on your state's average residential gas price, so the page works it out from your ZIP. Enter your ZIP in the cost calculator for your own area to see what 264 therms a year costs at your rate. The installed-cost range appears in its own block on this page, with its source and date.