RELIANCE WATER HEATERS ATO-140B-N 1**
0.81 UEF DOE CCD · 2026-09-19Grade G: where this UEF sits among the 80 models in its class, lowest (G) to highest (A). A position, not an official label. How the grade is set
A gas tankless unit, medium draw pattern (a typical three- or four-person household, about 55 gallons on a busy morning).
Checking the RELIANCE WATER HEATERS ATO-140B-N 1**? It is a gas tankless unit. At the medium draw pattern, the standard daily hot-water usage DOE tests against, it uses 137 therms of natural gas a year. That is 2 therms above the 135 therms median of the 80 models in its class.
Energy use per year
137 therms a year
Computed by this site from the registry's UEF and the federal test's daily hot-water draw for this draw pattern. What it costs depends on the natural gas rate where you live.
That is above the median of 135 therms for the 80 models registered in the same heater type and draw pattern; it ranks 52 of 80, lowest energy first.
Solid line: this model (137 therms). Dashed line: the class median.
Min 114 therms Median 135 therms Max 137 therms
What it costs to run where you live
What the registry files
- UEF (Uniform Energy Factor) how much hot water you get for each unit of energy the heater uses
- 0.81 DOE CCD · 2026-09-19 Compared only with other models registered as a gas tankless unit at the medium draw pattern.
- Draw Pattern the standard daily usage profile DOE tests the unit against
- Medium DOE CCD · 2026-09-19
- Maximum Gallons Per Minute how many gallons a minute it can heat while running continuously
- 3.6 gal/min DOE CCD · 2026-09-19
What it costs to install
$1,698–$2,632 installed
Not a quote — a modeled range of what installers have charged for this class of unit; your price will vary with labor rates, access, and local code requirements.
Escalation indexes: equipment (BLS PPI) latest available: August 2026; labor (BLS ECI) latest available: April 2026 to June 2026.
NLR REMDB (BLS PPI/ECI escalated) · 2026-04-01Safety record
No CPSC recall names this model.
Checked against the CPSC recall database. CPSC does not publish a model-level match for this product category, so this list is curated by hand from the manufacturer's recall filings.
CPSC · 2026-09-24What these figures mean
How this compares
The closest models in the same class — same fuel, type and draw pattern.
Keep going
How every figure on this page is calculated
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Find what replaces your water heater
Enter the model number off your old unit and see what is on file today, with the yearly cost difference.
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Find a water heater that fits
Three questions — fuel, hot water need, install space — narrow every model on file to the ones that fit.
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What a water heater costs to run
Prices a unit's efficiency against your own utility's filed tariff for your ZIP code.
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How to size a tankless water heater by GPM
Answered from what models in this size actually file.
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Water heaters
Every model on file with the Department of Energy, by heater type.
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All gas tankless water heaters
Gas-fired instantaneous units, sized by flow rate rather than tank gallons.
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Every RELIANCE WATER HEATERS model on file
What this brand files, by heater type.
UEF 0.81 · Grade G Price it on your ZIP
This site computed the figure of 137 therms of natural gas per year; the registry does not publish it. The calculation uses the registry's UEF, the ratio of hot water delivered to energy used, which is 0.81 for this model. It also uses the DOE test's daily hot-water draw for the medium pattern, a typical multi-person household on a busy morning. The source is DOE CCD, retrieved 2026-09-19. The maximum flow rate in gallons per minute is 3.6. That rating is listed for reference and is not an input to the annual figure. The method is set out on the methodology page for annual cost.
The class has 80 models registered as a gas tankless unit at the medium draw pattern. This one ranks 52nd lowest energy use. Its 137 therms sits 2 therms above the class median of 135 therms. That places it in the second-highest quarter of its class for energy use. A household whose hot-water use matches the medium pattern can compare 137 therms directly with other models in this class. A household with a different pattern should not use this figure, because the annual value is tied to the medium draw. The spread between the lowest and highest models in the class is not available here, so this page does not state it.
Running cost is not stated in the text. It depends on the state average residential gas price, so the page computes it from your ZIP. Use the cost calculator to apply your own rate to 137 therms. The result holds only for the medium pattern. If your household uses more or less hot water than that pattern, the result will change, and this page cannot say by how much. To compare with another unit in the same class, the same-class replacement finder works from a model number. The installed price range appears in its own block, as a modeled range, not a quote.
DOE CCD · 2026-09-19