Lochinvar GURT-50RL 4**

It holds 49 gallons in the test, 1 gallon less than its 50-gallon sold size. Starting full, it gives 92 gallons of hot water in its first hour of use. Its tank holds 49 gallons, so reheating adds 43 gallons during the first hour. In the first hour, 116 of the 763 gas storage models give more hot water. Among gas storage models, the median first-hour rating is 78 gallons.

On Oct 26, 2026, this heater was not listed as ENERGY STAR certified. In tests, 63% of the energy went to hot water, so its UEF is 0.63. Its test simulated a day of high hot water use (its draw pattern). Of 434 gas storage models with the same draw pattern, 339 have a higher UEF and 48 a lower one. On its draw pattern, the median gas storage UEF is 0.66. When it reheats water in the test, 77% of the energy it uses ends up in the water.

Its 2 model numbers are UTN05050-8R 4** and UTN05050R 4**. Its test figures match those of 3 other basic models. The A. O. Smith, American, and State brands list one or more of them. For the full group, see the A. O. Smith GURT-50RL 4**.