Ruud RHE40SP
0.75 UEF DOE CCD · 2026-09-19Grade A: 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 the Ruud RHE40SP, it uses 148 therms of natural gas a year at the medium draw pattern, the standard daily hot-water usage DOE tests against. That is 37 therms below the 185 therms median of the 288 gas tank models registered at the same draw pattern.
Energy use per year
148 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 1 of 288, lowest energy first.
Solid line: this model (148 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
- 0.75 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
- 68 gal DOE CCD · 2026-09-19
- Rated Storage Volume the tank size in gallons
- 37 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 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 Ruud model on file
What this brand files, by heater type.
UEF 0.75 · Grade A Price it on your ZIP
This site calculated the 148 therms figure on this page. The registry does not publish it. The figure combines the registry's UEF, the ratio of hot water delivered to energy used, with the DOE test's daily hot-water draw for the medium pattern. This model's UEF is 0.75, taken from DOE CCD data retrieved 2026-09-19. The medium pattern represents a typical household's hot-water demand, including a busy morning. A home that uses more hot water each day than the test assumes will use more gas. A home that uses less will use less gas. This page does not have figures for actual use in any one home. It shows only this test-condition value. The page on how the annual cost is calculated sets out each step of the calculation.
Within its class, the Ruud RHE40SP sits 37 therms below the 185 therms median at the medium draw pattern. It ranks 1st for lowest energy use out of 288 gas tank models tested at this pattern. That puts it in the lowest quarter of its class. The comparison covers only that class, so it does not rank this unit against electric or tankless heaters. Its first hour rating, the gallons of hot water available in the first hour from a full tank, is 68 gallons. The registry lists a rated tank volume of 37 gallons for this model. That rating does not cover a household that needs more than 68 gallons in its busiest hour. To look up models in the same class, use the same-class replacement search by model number.
This text does not state the running cost, because it depends on your state's average residential gas price. The page works it out from your ZIP by applying that price to the 148 therms test-condition figure. You can run the same calculation for another address with the cost calculator for your own ZIP. No installed price range is published for the RHE40SP. The cost database's model was fitted on a range of ratings, and this model's ratings fall outside that range. The site does not stretch that range to cover them. So this page cannot give an installed price for this unit. The 148 therms figure and the class rank are still shown on this page.
DOE CCD · 2026-09-19