Ariston GSN40T2-3-*

It holds 38 gallons in the test, 2 gallons less than its 40-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 32 gallons beyond the 38 gallons in its tank. In the first hour, 510 of the 763 gas storage models give more hot water. 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, 59% of the energy went to hot water, so its UEF is 0.59. Its test simulated a day of medium hot water use (its draw pattern). Its UEF is lower than that of 185 of the 288 gas storage models with its draw pattern. A UEF of 0.60 is the median for its type and draw pattern. The water took in 76% of the energy used to reheat it (its recovery efficiency).

All of its test figures are shared by one other basic model. That one carries the AMERICAN STANDARD WATER HEATERS brand name. For the full group, see the AMERICAN STANDARD WATER HEATERS GSN40T2-3-*.