Ariston GN30T1-3-*

It holds 29 gallons in the test, 1 gallon less than its 30-gallon sold size. Over one hour from a full tank, it gave 70 gallons in the test (its first-hour rating). Reheating lets it give 41 gallons beyond the 29 gallons in its tank. In the first hour, 510 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, 60% of the energy went to hot water, so its UEF is 0.60. Its test simulated a day of medium hot water use (its draw pattern). Its UEF is lower than that of 88 of the 288 gas storage models with its draw pattern. For its type and draw pattern, its UEF sits at the median. Of the energy spent to reheat water, 78% goes into it (its recovery efficiency).

There are 2 more basic models with the same test figures. Of those, one or more are under the AMERICAN STANDARD WATER HEATERS and Lennox brands. For the full group, see the AMERICAN STANDARD WATER HEATERS GN30T1-3-* page.