Lochinvar GCF-50 1**

It holds 48 gallons in the test, 2 gallons less than its 50-gallon sold size. It delivers 84 gallons of hot water in the test's first hour. That is 36 gallons more than its tank holds, since it reheats during the hour. Of 763 gas storage models, 209 give more hot water in the first hour. The median gas storage model gives 78 gallons in the first hour of the test.

As of Oct 26, 2026, it was not listed as ENERGY STAR certified. In tests, 69% of the energy it uses ends up as hot water (UEF 0.69). Its test simulated a day of high hot water use (its draw pattern). Of 434 gas storage models with the same draw pattern, 151 have a higher UEF and 249 a lower one. A UEF of 0.66 is the median for its type and draw pattern. The water took in 80% of the energy used to reheat it (its recovery efficiency).

It is sold as LTL05040ES 1*1 and LTN05040ES 1**. Its test figures match those of 6 other basic models. Each of them is listed under a different brand. You can find the whole group on the page for the A. O. Smith GCF-50 1**.

In 2 states, 2 rebate programs may accept it.