A. O. SMITH GCF-40 1**
0.64 UEF DOE CCD · 2026-09-19Grade E: 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 verifying this unit, the A. O. SMITH GCF-40 1** uses 173 therms of natural gas a year. That figure belongs to the medium draw pattern, the standard daily hot-water usage DOE tests against. It sits 12 therms below the class median of 185 therms across 288 gas tank models.
Energy use per year
173 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 44 of 288, lowest energy first.
Solid line: this model (173 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
- 0.64 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
- 70 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
$1,643–$2,763 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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All gas tank water heaters
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 0.64 · Grade E Price it on your ZIP
The registry lists a UEF, the ratio of hot water delivered to energy used, of 0.64 for this model. This site did not take the annual figure from the registry. It computed 173 therms from that UEF and the daily hot-water draw in the DOE test. The source is DOE CCD, retrieved 2026-09-19. The class median is 185 therms, so this model is 12 therms below it. It ranks 44th lowest in energy use of 288 models, in the lowest quarter of its class. The figure applies only at the test's daily draw. A household drawing more or less hot water will see a different total.
The first hour rating, the gallons of hot water available in the first hour from a full tank, is 70 gallons. The rated volume is 38 gallons. The energy figure suits a reader comparing gas tank models at the medium draw pattern, the group behind the 44th lowest rank. It does not suit a comparison with other fuels, because 173 therms counts natural gas only. It also does not cover a household whose morning draw exceeds the test's daily draw. This page does not judge whether a first hour rating of 70 gallons meets your peak hour. The water heater selector by fuel, space and size filters on those factors.
Running cost is not written here because it depends on your state average residential gas price. The cost calculator for your own ZIP applies that price to 173 therms. The method behind the annual cost is documented separately. The 12 therms gap to the class median of 185 therms is a gas quantity. What it is worth depends on the price you pay. The modeled installed-cost range is in its own block with its source and date. It is a modeled range, not a quote. To look for a same-class alternative, enter a model number in the replacement finder. Monthly bills and real household draw are not available on this page.
DOE CCD · 2026-09-19