A. O. SMITH GCFL-40 1**
0.66 UEF DOE CCD · 2026-09-19Grade D: where this UEF sits among the 288 models in its class, lowest (G) to highest (A). A position, not an official label. How the grade is set
A gas tank, medium draw pattern (a typical three- or four-person household, about 55 gallons on a busy morning).
If you are checking this listing: the A. O. SMITH GCFL-40 1**, a gas tank heater, uses 168 therms of natural gas a year at the medium draw pattern, the standard daily hot-water usage DOE tests against. That is 17 therms below the 185 therms median of 288 comparable models.
Energy use per year
168 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 below the median of 185 therms for the 288 models registered in the same heater type and draw pattern; it ranks 27 of 288, lowest energy first.
Solid line: this model (168 therms). Dashed line: the class median.
Min 148 therms Median 185 therms Max 194 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
- 0.66 DOE CCD · 2026-09-19 Compared only with other models registered as a gas tank at the medium draw pattern.
- Draw Pattern the standard daily usage profile DOE tests the unit against
- Medium DOE CCD · 2026-09-19
- First Hour Rating how many gallons of hot water the unit can deliver in one hour, starting from a full tank
- 65 gal DOE CCD · 2026-09-19
- Rated Storage Volume the tank size in gallons
- 38 gal DOE CCD · 2026-09-19
What it costs to install
$1,760–$3,064 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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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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Is a 40-gallon water heater enough?
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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Gas-fired storage tanks, every size and draw pattern on file.
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Every A. O. SMITH model on file
What this brand files, by heater type.
UEF 0.66 · Grade D Price it on your ZIP
The registry lists a UEF, the ratio of hot water delivered to energy used, of 0.66 for this model. The registry does not publish an annual energy figure. This site computed 168 therms from that UEF and the DOE test's daily hot-water draw for the medium draw pattern, using data from DOE CCD retrieved 2026-09-19. The figure holds only for natural gas and only at that draw. Among the 288 models registered as a gas tank at the medium draw pattern, this one has the 27th lowest energy use, which puts it in the lowest quarter of its class. The gap to the 185 therms class median is 17 therms. The steps are set out in how the annual cost is calculated.
The medium draw pattern stands for a typical household on a busy morning, and 168 therms is the figure for that draw. The registry lists a first hour rating, the gallons of hot water available in the first hour from a full tank, of 65 gallons for this model. It lists a rated volume of 38 gallons. A household whose morning demand is close to the medium draw pattern is the case these numbers describe. A household with a higher or lower draw is not covered by 168 therms, and the data here gives no figure for other draw patterns. The registry also does not say whether a first hour rating of 65 gallons meets a particular home's demand. The water heater selector by fuel, space and size filters models by those inputs.
Running cost is not stated in this text because it depends on the state average residential gas price, which differs by reader. The page computes it from your ZIP, and the 168 therms figure is the energy input to that calculation. The 17 therms gap to the class median is a difference in energy only. What it means in cost depends on your own rate, and this page gives no estimate of it. The cost calculator on your own ZIP applies your state's price to the same figure. If you are comparing this GCFL-40 1** with another unit of the same class, use find a same-class replacement by model number. The installed price range appears in its own block with its source and date.
DOE CCD · 2026-09-19