ARISTON PV40TLN*50*

The registry lists a UEF, the ratio of hot water delivered to energy used, of 0.7 for this model. The registry does not state annual energy. This site computed 242 therms of natural gas from that UEF and the DOE test's daily hot-water draw for the high draw pattern, using data from DOE CCD retrieved 2026-09-19. The figure applies only at that test draw. Among 414 models, this one ranks 90th lowest for energy use, which places it in the lowest quarter of its class. The steps of the calculation are set out on the methodology page.

The high draw pattern describes a larger household, or one where showers and laundry overlap. This model suits a reader whose hot-water use is close to that test draw, because 242 therms holds only at that draw. It has a first hour rating, the gallons of hot water available in the first hour from a full tank, of 83 gallons, and a rated volume of 38 gallons. This page does not compare that rating with any household's peak demand. A reader whose use is well above or below the test draw should expect a different annual figure, and that figure is not available here. The water heater selector filters by fuel, space and size.

Running cost is not stated in the text, because it depends on your state's average residential gas price. Multiplying 242 therms by your own rate gives the yearly cost at the test draw, and the cost calculator does this from your ZIP. The gap to the class median is 18 therms, against a median of 260 therms. The cost of that gap depends on the same rate, and this page does not estimate it. To compare a unit in the same class, use the same-class replacement search by model number. The modeled installed-cost range is shown in its own block with its source and date.