LOCHINVAR TK-510C-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 a larger household, or one where showers and laundry overlap, the LOCHINVAR TK-510C-NI 1** uses 209 therms of natural gas a year at the high draw pattern, the standard daily hot-water usage DOE tests against. That is 27 therms above the class median of 182 therms.
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
- 4.7 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 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 LOCHINVAR model on file
What this brand files, by heater type.
UEF 0.81 · Grade G Price it on your ZIP
The registry lists this LOCHINVAR TK-510C-NI 1** as a gas tankless unit with a UEF, the ratio of hot water delivered to energy used, of 0.81. This site did not take the annual figure from the registry. It computed 209 therms of natural gas from that UEF and the daily hot-water draw in the DOE test for the high draw pattern, using data from DOE CCD retrieved 2026-09-19. The figure applies only under that condition. The comparison group is the 397 models registered as a gas tankless unit at the high draw pattern. The class median in that group is 182 therms, and this model sits 27 therms above it.
This model ranks 323rd lowest in energy use of 397, which places it in the highest quarter of its class for energy use. A reader who wants the lowest gas use within this class should know that the models ranked before it use less gas at the same draw pattern. The unit does match the situation the high draw pattern describes: a larger household, or one where showers and laundry overlap. The registry lists its maximum flow rate in gallons per minute as 4.7. That rating is a separate measure from annual energy and does not change the rank. The energy figure does not apply to a household with lighter use, because DOE tests that use under a different draw pattern. The water heater selector filters by fuel, space and size, and the replacement finder lists same-class models by model number.
The running cost is not stated here because it depends on the average residential gas price in your state. Multiply the 209 therms by your local price per therm to get a yearly cost at the high draw pattern, or use the cost calculator for your ZIP. The methodology page explains how the annual cost is calculated. Any result carries the same limit as the energy figure: it assumes the federal test's daily draw, not your actual hot-water use. Actual household use is not available in the registry data. The modeled installed-cost range appears in its own block on the page with its source and date. It is a modeled range, not a quote, and this text does not restate it.
DOE CCD · 2026-09-19