Ariston GN30T2-3-*

It holds 29 gallons in the test, 1 gallon less than its 30-gallon sold size. Starting full, it gives 67 gallons of hot water in its first hour of use. That is 38 gallons more than its tank holds, since it reheats during the hour. Of 763 gas storage models, 552 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, 60% of the energy it uses ends up as hot water (UEF 0.60). Its test ran at the medium level of daily hot water use. Its UEF is lower than that of 88 of the 288 gas storage models with its draw pattern. Its UEF is the median for its type and draw pattern. When it reheats water in the test, 77% of the energy it uses ends up in the water.

All of its test figures are shared by one other basic model. The brand name on that one is AMERICAN STANDARD WATER HEATERS. For the full group, see the AMERICAN STANDARD WATER HEATERS GN30T2-3-* page.