Lochinvar GCFL-40 1**

It holds 38 gallons in the test, 2 gallons less than its 40-gallon sold size. It delivers 65 gallons of hot water in the test's first hour. Reheating lets it give 27 gallons beyond the 38 gallons in its tank. Among 763 gas storage models, 600 have a higher first-hour rating. The median gas storage model gives 78 gallons in the first hour of the test.

It was not listed as ENERGY STAR certified on Oct 26, 2026. In tests, 66% of the energy it uses ends up as hot water (UEF 0.66). Its test ran at the medium level of daily hot water use. Its UEF is lower than that of 26 of the 288 gas storage models with its draw pattern. For its type and draw pattern, the median UEF is 0.60. Of the energy spent to reheat water, 77% goes into it (its recovery efficiency).

It is the basic model for LSL04040ES 1*1 and LSN04040ES 1**. All of its test figures are shared by 5 other basic models. Each of the 5 other brands lists one of them. You can find the whole group on the page for the A. O. Smith GCFL-40 1**.

It may qualify for one rebate program.