NAVIEN NHW700-160SE-NG

The figure of 209 therms is computed by this site, not the registry. Its inputs are the registry's UEF, the ratio of hot water delivered to energy used, of 0.81, and the DOE test's daily hot-water draw. The source is DOE CCD, retrieved 2026-09-19. The registry lists a maximum flow rate in gallons per minute of 4. Against the 397 models registered as a gas tankless unit at the high draw pattern, its energy use is 27 therms above the class median of 182 therms. That places it in the highest quarter of its class for energy use, at 323rd lowest of 397.

The high draw pattern describes a larger household, or one where showers and laundry overlap. The figure of 209 therms applies only to that pattern. This page does not show a figure for any other draw pattern for this model, so none is stated. A household that matches the high draw pattern can compare 209 therms directly with the class median of 182 therms. A household that uses less hot water than the federal test's daily draw should expect a different figure, but the size of the difference is not available here. The maximum flow of 4 gallons per minute is a rated limit, not a measure of energy use. To compare units by fuel, space and size, use the water heater selector.

The running cost is not written in the text because it depends on your state's average residential gas price. The 209 therms of natural gas at the high draw pattern is the quantity that price multiplies. The cost calculator on your own ZIP applies your state's rate to it, and how the annual cost is calculated is documented separately. Because this unit sits 27 therms above the class median of 182 therms, a model at the median would use that many fewer therms a year at the same draw pattern. You can find a same-class replacement by model number and compare. The modeled installed-cost range appears in its own block with its source and date; it is a range, not a quote.