BRADFORD WHITE RTGS150N1

The 173 therms figure is computed by this site. The registry does not publish it. It starts from the registry's UEF, the ratio of hot water delivered to energy used, which is 0.98 for this model. The second input is the DOE test's daily hot-water draw for the high draw pattern. Both inputs come from the DOE CCD, retrieved 2026-09-19. The figure therefore describes the federal test's daily usage, not a measured household. A home that draws more hot water each day than the test would use more gas than 173 therms. A home that draws less would use less. The unit's maximum flow rate in gallons per minute, 4.3, is a separate registry value. It limits how much hot water flows at once and is not part of the annual energy calculation.

The high draw pattern stands for a larger household, or one where showers and laundry overlap. Among the 397 models registered as a gas tankless unit at that pattern, the median is 182 therms a year. This model uses 9 therms less than that median and ranks 1st for lowest energy use among the 397. That places it in the lowest quarter of its class for energy use. The rank covers annual energy use only. The registry data on this page says nothing about other qualities. The comparison does not cover models tested at a lower draw pattern, because those sit in other classes. To compare another model number in the same class, use find a same-class replacement by model number. For other fuels or sizes, the selector by fuel, space and size lists them.

This page does not give a running cost in the text. The cost of 173 therms of natural gas depends on your state's average residential gas price. The page therefore computes it from your ZIP. The cost calculator on your own ZIP applies that rate to this model's figure. The steps are explained in how the annual cost is calculated. Applying the same rate to the 182 therms class median shows what the 9 therms gap amounts to at your price. The installed price appears in its own block, with its source and date. It is a modeled installed-cost range, not a quote. Energy use and installed price are separate figures, and neither one includes the other.