NAVIEN NHW700-180SU-NG
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).
Checking the NAVIEN NHW700-180SU-NG, a gas tankless unit? At the high draw pattern, the standard daily hot-water usage DOE tests against, it uses 209 therms of natural gas a year. That is 27 therms above its class median of 182 therms. It ranks 323rd for lowest energy use among 397 comparable models.
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 NAVIEN model on file
What this brand files, by heater type.
UEF 0.81 · Grade G Price it on your ZIP
The 209 therms figure is not taken directly from the registry. This site calculated it. It starts from the registry's UEF, the ratio of hot water delivered to energy used, which is 0.81 for this model. That rating is applied to the DOE test's daily hot-water draw for the high draw pattern. The source is the DOE CCD, retrieved 2026-09-19. The figure applies only at that test draw. A home that uses more hot water a day than the test assumes will use more gas, and a home that uses less will use less. This registry data does not show how far your own use differs from the test draw. The steps behind the figure are explained in how the annual energy and cost figures are calculated.
The high draw pattern stands for a larger household, or one where showers and laundry overlap. This model is rated for that pattern. Its maximum flow rate in gallons per minute is 4.8, which is the most hot water it is rated to deliver at one time. Among the 397 gas tankless units registered at the high draw pattern, its energy use puts it in the highest quarter of the class. If low gas use at this draw matters most to you, note that most models in the class use less. To compare those models on the same terms, use the same-class replacement search by model number. You can also filter by fuel, space and size in the water heater selector. This data does not say how the unit performs in a smaller household, because every figure here applies to the high draw only.
The running cost is not written in this text because it depends on your own gas rate. The page works it out by applying your state's average residential natural gas price, found from your ZIP, to the 209 therms test-draw figure. No cost figure is given here. Do not work one out from the class median of 182 therms. To see the result for your state, enter your ZIP in the cost calculator for your own ZIP. The installed price range has its own block on this page, with its source and date. It is a modeled installed-cost range, not a quote from an installer. Both results assume the high draw pattern. A home that uses a different amount of hot water each day will get different figures, and this data does not provide them.
DOE CCD · 2026-09-19