RELIANCE WATER HEATERS ATI-140B-N 1**

This model has a UEF, the ratio of hot water delivered to energy used, of 0.81. This site computed the 137 therms figure from that UEF and the DOE test's daily hot-water draw for the medium draw pattern. The registry does not publish the annual figure itself. The source is DOE CCD, retrieved 2026-09-19. The comparison group is the 80 models registered as a gas tankless unit at the same draw pattern. Their median is 135 therms, so this model sits 2 therms above it. Its rank of 52nd lowest of 80 places it in the second-highest quarter of its class for energy use.

The medium draw pattern describes a typical household on a busy morning, so the figure is most relevant to a home that uses hot water about that way. It does not describe other draw patterns, and this page has no energy figure for them. The unit's maximum flow rate in gallons per minute is 3.6. The data here does not give the temperature rise that flow rate assumes, so it is not available. A household whose use differs from the medium pattern should treat 137 therms as a test-based reference, not a prediction. To compare other fuels, spaces or sizes, use the water heater selector. To check same-class alternatives, find a replacement by model number.

The running cost is not stated in this text because it depends on your state's average residential gas price. Multiply 137 therms by that price per therm to see the annual cost for this model. The cost calculator does this from your ZIP. The methodology page explains how the annual cost is calculated. Because this model is 2 therms above the class median of 135 therms, the same price gives a cost close to the median model's, and the exact difference depends on your rate. The modeled installed-cost range appears in its own block on this page with its source and date. It is a modeled range, not a quote, and it is not repeated here. Metered use in your home is not available and may differ from the test draw.