A. O. SMITH GUC-30 4**
0.59 UEF DOE CCD · 2026-09-19Grade G: 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 the A. O. SMITH GUC-30 4** gas tank water heater, it uses 188 therms of natural gas a year. That figure belongs to the medium draw pattern, the standard daily hot-water usage DOE tests against. It is 3 therms above the 185 therms median of the 288 gas tank models registered at that draw pattern.
Energy use per year
188 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 185 therms for the 288 models registered in the same heater type and draw pattern; it ranks 186 of 288, lowest energy first.
Solid line: this model (188 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
- 0.59 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
- 62 gal DOE CCD · 2026-09-19
- Rated Storage Volume the tank size in gallons
- 29 gal DOE CCD · 2026-09-19
What it costs to install
Not published: Installed cost range
This model's rated tank size lies outside the range NLR REMDB's cost model was fitted on, and the range is not stretched past it.
The annual energy figure on this page does not depend on this range and is unaffected.
Safety 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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Is a 30-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 0.59 · Grade G Price it on your ZIP
The registry does not print the 188 therms figure. This site computed it from two inputs. The first is the model's UEF, the ratio of hot water delivered to energy used, which is 0.59. The second is the DOE test's daily hot-water draw for the medium draw pattern. The source is the DOE CCD, retrieved 2026-09-19. This unit ranks 186th lowest in energy use among the 288 gas tank models at this draw pattern. That places it in the second-highest quarter of its class for energy use. The figure holds only at the test's daily draw. If your household uses more or less hot water than the test assumes, your actual use will differ. This data does not show by how much.
The figures describe a home whose daily hot-water use is close to the medium draw pattern. The model's first hour rating, the gallons of hot water available in the first hour from a full tank, is 62 gallons. Its rated volume is 29 gallons. A home with heavier morning demand than the medium pattern falls outside what these figures describe. For that case, compare other sizes with the water heater selector by fuel, space and size. If you are checking a proposed swap, you can find a same-class replacement by model number. You can then compare its annual energy use at the same draw pattern against 188 therms.
The running cost is not given in this text. It depends on your state's average residential natural gas price. The page computes it from your ZIP, and you can also run the cost calculator on your own ZIP. The steps behind that result are set out in how the annual cost is calculated. At any rate, the 3 therms gap is gas this model uses each year beyond the class median of 185 therms. An installed price range is not published for this model. Its ratings lie outside the range the cost database's model was fitted on. The site does not stretch that range past its fitted limits.
DOE CCD · 2026-09-19