ARISTON GSN50T1-3-*

The figure of 260 therms was computed by this site, not by the registry. It combines the registry's UEF, the ratio of hot water delivered to energy used, with the daily hot-water draw the DOE test assigns to the high draw pattern. The UEF of this model is 0.65. The source is the DOE CCD, retrieved 2026-09-19. The figure holds only for natural gas and only at that draw pattern. A household that uses more or less hot water than the test assumes will use a different amount of energy, and that measured difference is not available here. The calculation steps are set out under how the annual cost is calculated.

This model is compared with the 414 models registered as a gas tank at the high draw pattern. It ranks 204th lowest in energy use of 414, which places it in the second-lowest quarter of its class for energy use. The class median is 260 therms, and this model's difference from it is 0 therms, so it is equal to the median. The rank reflects energy use at the federal test's daily draw only. It does not describe how the unit performs in a home with different habits, and the registry data used here do not measure that.

This model suits a household that matches the high draw pattern: a larger household, or one where showers and laundry overlap. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 86 gallons, and its rated volume is 47 gallons. It does not suit a reader who needs a figure for a different draw pattern, because 260 therms applies only to the high one. The running cost depends on your state's average residential gas price, so the text does not state it. Use the cost calculator on your own ZIP to see it, or the selector by fuel, space and size to look at other options. The modeled installed-cost range appears in its own block.