Lennox WHGS040T40PAXS****
0.6 UEF DOE CCD · 2026-09-19Grade F: 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 your household matches the medium draw pattern, the standard daily hot-water usage DOE tests against, the Lennox WHGS040T40PAXS**** gas tank uses 185 therms of natural gas a year. That equals the class median of 185 therms, a difference of 0 therms, and ranks 89th lowest of 288 models.
Energy use per year
185 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 equal to the median of 185 therms for the 288 models registered in the same heater type and draw pattern; it ranks 89 of 288, lowest energy first.
Solid line: this model (185 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
- 0.6 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
- 74 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
$1,410–$2,162 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.
-
Is a 40-gallon water heater enough?
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 tank water heaters
Gas-fired storage tanks, every size and draw pattern on file.
-
Every Lennox model on file
What this brand files, by heater type.
UEF 0.6 · Grade F Price it on your ZIP
The annual figure is computed by this site, not published by the registry. It combines the registry's UEF, the ratio of hot water delivered to energy used, of 0.6 with the daily hot-water draw DOE assigns to the medium pattern. The source is DOE CCD, retrieved 2026-09-19. The result, 185 therms of natural gas, holds only at that test draw. A household that draws more or less hot water will use a different amount. The unit sits in the second-lowest quarter of its class for energy use, and that position describes energy use only. It says nothing about hot-water capacity, and the registry data does not include measured energy use in a real home.
Capacity is separate from energy use. The registry lists a first hour rating, the gallons of hot water available in the first hour from a full tank, of 74 gallons, and a rated volume of 38 gallons. These figures are most relevant to a household whose demand resembles the medium draw pattern, because the energy figure was calculated for that pattern. A household with a much larger or smaller daily draw should not expect the 185 therms figure to carry over. The registry does not state a household size limit for this model, so that fit is unknown. To compare options by fuel, space and size, use the water heater selector. To look for a same-class unit starting from WHGS040T40PAXS****, use the replacement search by model number.
The registry does not give a running cost, and this text does not either, because it depends on your state's average residential gas price. Multiply 185 therms by that price per therm to get a yearly figure for the medium draw pattern. Because the difference from the class median is 0 therms, this model's running cost at any given gas price equals that of a median unit in its class under the same test draw. Enter your ZIP in the cost calculator to see the result on your own rate, and read how the annual cost is calculated for the method. The modeled installed-cost range appears in its own block with its source and date. It is a modeled range, not a quote, and it is not restated here.
DOE CCD · 2026-09-19