THERMALUX NRC98DV (GQ-C2857WS-FF US)
0.91 UEF DOE CCD · 2026-09-19Grade C: 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 THERMALUX NRC98DV (GQ-C2857WS-FF US), it uses 186 therms of natural gas a year at the high draw pattern, the standard daily hot-water usage DOE tests against. That sits 4 therms above the 182 therms median of the 397 gas tankless models registered at that pattern. This site computed the figure from the registry's rating.
Energy use per year
186 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 213 of 397, lowest energy first.
Solid line: this model (186 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
- 0.91 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
- 5.1 gal/min DOE CCD · 2026-09-19
What it costs to install
$2,169–$3,184 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.
UEF 0.91 · Grade C Price it on your ZIP
The 186 therms figure is not a registry value. This site computed it from the registry's UEF, the ratio of hot water delivered to energy used, which is 0.91 for this model. It combines that rating with the DOE test's daily hot-water draw for the high pattern. The figure therefore holds at that test draw, not at your household's actual use. The source is DOE's Compliance Certification Database (CCD), retrieved 2026-09-19. The page on how the annual cost is calculated sets out the method. If your household draws less hot water than the test assumes, gas use would fall below 186 therms. If it draws more, use would rise above it. The registry gives no figure for other draw levels, so those values are not available here.
Among the 397 gas tankless models registered at the high draw pattern, this one ranks 213th lowest in annual energy use. That places it in the second-highest quarter of its class for energy use. The high pattern stands for a larger household, or one where showers and laundry overlap. A home matching that description is the case the 186 therms figure describes. The registered maximum flow rate in gallons per minute is 5.1 for this model. For a smaller household, this page's figure does not apply directly. A value for this model at a lower draw pattern is not available in the data. To compare units in the same class, you can find a same-class replacement by model number.
This text states no running cost for the NRC98DV (GQ-C2857WS-FF US). Cost depends on your state's average residential gas price, so the page computes it from your ZIP. The input is the same 186 therms a year at the high draw pattern. Readers in different states will therefore see different costs for this model. You can apply that figure to your own rate with the cost calculator for your ZIP. The installed-price block on this page is a separate item. It shows a modeled installed-cost range with its own source and date, not a quote. How much the 4 therms gap to the class median changes your yearly cost depends on your rate. This text does not know that rate.
DOE CCD · 2026-09-19