RELIANCE WATER HEATERS TK-310U-E 2**
0.81 UEF DOE CCD · 2026-09-19Grade G: where this UEF sits among the 397 models in its class, lowest (G) to highest (A). A position, not an official label. How the grade is set
A gas tankless unit, high draw pattern (a larger household, or one where showers and laundry overlap).
If you are checking the RELIANCE WATER HEATERS TK-310U-E 2**, a gas tankless unit, it uses 209 therms of natural gas a year. That figure applies at the high draw pattern, the standard daily hot-water usage DOE tests against. It is 27 therms above the 182 therms median of the 397 gas tankless models registered at the same draw pattern.
Energy use per year
209 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 182 therms for the 397 models registered in the same heater type and draw pattern; it ranks 323 of 397, lowest energy first.
Solid line: this model (209 therms). Dashed line: the class median.
Min 173 therms Median 182 therms Max 209 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
- 0.81 DOE CCD · 2026-09-19 Compared only with other models registered as a gas tankless unit at the high draw pattern.
- Draw Pattern the standard daily usage profile DOE tests the unit against
- High DOE CCD · 2026-09-19
- Maximum Gallons Per Minute how many gallons a minute it can heat while running continuously
- 4.8 gal/min DOE CCD · 2026-09-19
What it costs to install
$1,698–$2,632 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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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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How to size a tankless water heater by GPM
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 tankless water heaters
Gas-fired instantaneous units, sized by flow rate rather than tank gallons.
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Every RELIANCE WATER HEATERS model on file
What this brand files, by heater type.
UEF 0.81 · Grade G Price it on your ZIP
This site calculates the 209 therms figure; the registry does not state it. It 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 high draw pattern. For the RELIANCE WATER HEATERS TK-310U-E 2**, the UEF is 0.81. The rating comes from DOE's Compliance Certification Database, retrieved 2026-09-19. The yearly figure holds only at that federal test draw. The registry data do not give gas use at a different daily draw. The steps behind the figure are set out on the page on how the annual cost is calculated.
The high draw pattern describes a larger household, or one where showers and laundry overlap. This unit is rated at a maximum flow rate in gallons per minute of 4.8. Among the 397 models in its class, it ranks 323rd for lowest energy use. That places it in the highest quarter of the class for energy use at the same test draw. A comparison against this class is therefore a comparison between units rated at the high draw pattern. To see other models registered in the same class, use the page to find a same-class replacement by model number.
At the high draw pattern, the class median is 182 therms, which is 27 therms below this model's yearly figure. The registry data give no reason for that gap beyond the rating itself. The running cost is not given in this text, because it depends on your state's average residential gas price. The page applies that price, found from your ZIP, to the 209 therms figure. Enter your ZIP in the cost calculator for your own ZIP to see the yearly cost at your rate. The modeled installed-cost range appears in its own block, with its source and date. That range is not a quote.
DOE CCD · 2026-09-19