A. O. SMITH ATI-199B-N 1**
0.82 UEF DOE CCD · 2026-09-19Grade G: where this UEF sits among the 397 models in its class, lowest (G) to highest (A). A position, not an official label. How the grade is set
A gas tankless unit, high draw pattern (a larger household, or one where showers and laundry overlap).
If you are checking the A. O. SMITH ATI-199B-N 1**, a gas tankless unit, the figure to know is 206 therms of natural gas a year at the federal test's high daily hot-water draw. That is 24 therms above the 182 therms class median, across 397 registered models.
Energy use per year
206 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 182 therms for the 397 models registered in the same heater type and draw pattern; it ranks 229 of 397, lowest energy first.
Solid line: this model (206 therms). Dashed line: the class median.
Min 173 therms Median 182 therms Max 209 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
- 0.82 DOE CCD · 2026-09-19 Compared only with other models registered as a gas tankless unit at the high draw pattern.
- Draw Pattern the standard daily usage profile DOE tests the unit against
- High DOE CCD · 2026-09-19
- Maximum Gallons Per Minute how many gallons a minute it can heat while running continuously
- 5.2 gal/min DOE CCD · 2026-09-19
What it costs to install
$1,745–$2,687 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 A. O. SMITH model on file
What this brand files, by heater type.
UEF 0.82 · Grade G Price it on your ZIP
The registry gives this model a UEF, the ratio of hot water delivered to energy used, of 0.82. This site combined that UEF with the daily hot-water draw DOE uses for the high draw pattern, the standard daily hot-water usage DOE tests against. The result is 206 therms of natural gas per year. The high pattern describes a larger household, or one where showers and laundry overlap. The registry does not publish this annual figure. The site computed it from DOE CCD data retrieved 2026-09-19. Among the 397 models registered as a gas tankless unit at the high draw pattern, this one ranks 229th lowest for energy use. That places it in the second-highest quarter of its class for energy use.
The class median is 182 therms, so this model sits 24 therms above it under the same test conditions. Models ranked ahead of it use less gas at that draw. The figure suits a reader who wants to confirm a listing against the registry at the high draw pattern, or to see where the model falls in its class. It does not describe a household whose hot-water use differs from the federal test draw, and the registry data does not show how this model performs in such a home. The maximum flow rate in gallons per minute is 5.2. The data does not say whether that covers a given home's simultaneous demand. For other fuels, spaces or sizes, use the selector by fuel, space and size.
The running cost is not stated here because it depends on your state's average residential gas price. Multiplying 206 therms by that price gives the yearly cost at the test draw. Multiplying 24 therms by the same price gives the yearly cost of the gap to the class median of 182 therms. The cost calculator on your own ZIP does this with your state's price, and the annual cost methodology explains each step. The modeled installed-cost range appears in its own block on the page, with its source and date. Actual gas use in a home will differ from the test figure, and the registry data contains no measurements from real homes. To compare against a same-class unit, find a replacement by model number.
DOE CCD · 2026-09-19