FRIEDRICH PROG40S-36N RH67 PV

The 171 therms figure is not a measurement taken from this unit in a home. This site computed it from the registry's UEF, the ratio of hot water delivered to energy used, which is 0.65 for this model, and from the DOE test's daily hot-water draw for the medium draw pattern. The source is DOE CCD, retrieved 2026-09-19. The class is the 288 models registered as a gas tank at this draw pattern, and its median is 185 therms. This model sits 14 therms below that median and ranks 33rd lowest, which places it in the lowest quarter of its class for energy use. The annual cost method is documented on its own page.

The model has a first hour rating, the gallons of hot water available in the first hour from a full tank, of 66 gallons. Its rated volume is 39 gallons. The 171 therms figure applies to a household whose hot-water use matches the medium draw pattern. A household that draws more or less will use a different amount of gas, and the data here does not say how much different. The figure also covers natural gas only, so it should not be set beside the energy use of a unit that runs on another fuel. To filter by fuel, space and size, use the water heater selector.

A running cost is not written here because it depends on the state average residential gas price, and that price differs between readers. Multiply the 171 therms by your own gas rate, or enter your ZIP in the cost calculator to get the result. The 14 therms gap to the class median of 185 therms is in the same unit, so the same rate turns it into a yearly difference against a median model in this class. The modeled installed-cost range appears in its own block with its source and date. It is a modeled range, not a quote. To compare with a same-class model, you can find a replacement by model number.