A. O. SMITH TK-110U-E 2**
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).
You are verifying this unit's federal figure. The A. O. SMITH TK-110U-E 2** uses 137 therms of natural gas a year at the medium draw pattern, the standard daily hot-water usage DOE tests against. That is 2 therms above the class median of 135 therms across 80 gas tankless models. It ranks 52nd lowest for energy use.
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
- 3.5 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
-
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.
-
Find a water heater that fits
Three questions — fuel, hot water need, install space — narrow every model on file to the ones that fit.
-
What a water heater costs to run
Prices a unit's efficiency against your own utility's filed tariff for your ZIP code.
-
How to size a tankless water heater by GPM
Answered from what models in this size actually file.
-
Water heaters
Every model on file with the Department of Energy, by heater type.
-
All gas tankless water heaters
Gas-fired instantaneous units, sized by flow rate rather than tank gallons.
-
Every A. O. SMITH model on file
What this brand files, by heater type.
UEF 0.81 · Grade G Price it on your ZIP
The annual figure of 137 therms was computed by this site, not by the registry. It combines the registry's UEF, the ratio of hot water delivered to energy used, with the daily hot-water draw in the DOE test. The registry lists a UEF of 0.81 for this model. The figure applies only to the medium draw pattern, which describes a typical household on a busy morning. The source is DOE CCD, retrieved 2026-09-19. Another draw pattern would give a different figure, and none is available here. The method behind the annual calculation is documented separately.
Compare it with the 80 models registered as a gas tankless unit at the medium draw pattern. This unit sits 2 therms above the class median of 135 therms. It ranks 52nd lowest in energy use, in the second-highest quarter of its class. The maximum flow rate in gallons per minute is 3.5. The data does not show how the ranking changes at other draw patterns. The figure fits a household whose daily use resembles the medium pattern. It fits less well a reader who wants use at or below the class median of 135 therms. To look at other units, use the selector by fuel, space and size or find a same-class replacement by model number.
The running cost is not stated in the text because it depends on your gas price. The page computes it from your ZIP, using the state average residential gas price. Use the cost calculator on your own ZIP to see it. The calculator starts from the same 137 therms at the medium draw pattern. The 2 therms difference from the class median is priced at your same rate. A modeled installed-cost range appears in its own block with its source and date. It is a modeled range, not a quote. Measured use in a home is not available in this data, so the figure is a test-based calculation, not a measured bill.
DOE CCD · 2026-09-19