RELIANCE WATER HEATERS TK-310C-NI 1**
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).
For anyone checking this model's rated figures: the RELIANCE WATER HEATERS TK-310C-NI 1**, a gas tankless unit, 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 sits 27 therms above its class median of 182 therms, ranking 323rd lowest in energy use of 397.
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
- 4.6 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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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 calculated the 209 therms figure; the registry does not list 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 pattern. For this model the UEF is 0.81. The high draw pattern describes a larger household, or one where showers and laundry overlap. The registry record comes from the DOE Compliance Certification Database (CCD), retrieved 2026-09-19. The figure holds only at the federal test's daily draw. This page has no figure for a home that uses more or less hot water than the test assumes. The steps behind the calculation are set out in how this site calculates annual energy and cost.
The rank given above puts this unit in the highest quarter of its class for energy use. At the high draw pattern, most gas tankless units registered in that class use less gas than its 209 therms. Its maximum flow rate in gallons per minute is 4.6. These figures are relevant to a household that matches the high pattern. For a reader who wants lower gas use at the same pattern, this model's figures are higher than most in its class. That reader can compare it against same-class replacements by model number. The data here does not cover reliability, noise or service history, so this page cannot say anything about them.
The running cost of 209 therms a year depends on the price of natural gas where the reader lives. The text does not state a cost, because the state average residential gas price differs from state to state. The cost calculator for your own ZIP applies your state's rate to this model's annual gas use. Its result is only valid at the high draw pattern and the test's daily draw. The installed-cost range appears in its own block on this page, with its source and date. That range is modeled, not a quote from an installer. For other fuels or sizes, see the water heater selector by fuel, space and size.
DOE CCD · 2026-09-19