NAVIEN NPE-240S2
0.96 UEF DOE CCD · 2026-09-19Grade A: 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 NAVIEN NPE-240S2, this site computes 176 therms of natural gas a year from its registry rating. That figure holds at the high draw pattern, the standard daily hot-water usage DOE tests against. It sits 6 therms below the 182 therms median of the 397 gas tankless units registered at that pattern.
Energy use per year
176 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 below the median of 182 therms for the 397 models registered in the same heater type and draw pattern; it ranks 12 of 397, lowest energy first.
Solid line: this model (176 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
- 0.96 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
- 5.8 gal/min DOE CCD · 2026-09-19
- On the market since (ENERGY STAR) the date the manufacturer told ENERGY STAR the model went on sale
- 2021-01-01 ENERGY STAR · 2026-09-19
- Connected / demand response (ENERGY STAR) whether the unit can take signals from your utility to shift when it heats, and by which standard (such as CTA-2045)
- No ENERGY STAR · 2026-09-19
What it costs to install
$2,405–$3,460 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 · 2026-09-24Does it fit your space?
Enter your own numbers below — this compares them to what ENERGY STAR publishes for this model, it does not tell you what to buy.
- Dimensions (ENERGY STAR)
- the unit's filed height, width, depth or tank diameter, in inches
- Input voltage and maximum current (ENERGY STAR)
- the circuit voltage the unit is certified on and the most current it draws
- Vent type and size (ENERGY STAR)
- how a gas unit is vented, the vent's diameter and the height of its vent connector
What 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
-
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.
-
Find a water heater that fits
Three questions — fuel, hot water need, install space — narrow every model on file to the ones that fit.
-
What a water heater costs to run
Prices a unit's efficiency against your own utility's filed tariff for your ZIP code.
-
How to size a tankless water heater by GPM
Answered from what models in this size actually file.
-
Water heaters
Every model on file with the Department of Energy, by heater type.
-
All gas tankless water heaters
Gas-fired instantaneous units, sized by flow rate rather than tank gallons.
-
Every NAVIEN model on file
What this brand files, by heater type.
UEF 0.96 · Grade A Price it on your ZIP
The 176 therms figure starts from the model's UEF, the ratio of hot water delivered to energy used. The DOE Compliance Certification Database (CCD) lists it as 0.96, retrieved 2026-09-19. This site, not the registry, turns that rating into a yearly figure. It applies the DOE test's daily hot-water draw for the high pattern, which describes a larger household, or one where showers and laundry overlap. Among the 397 gas tankless models at that pattern, this model has the 12th lowest energy use. That places it in the lowest quarter of its class. The 6 therms gap to the 182 therms median holds only at the test's draw. A household that draws more or less hot water will see a different figure. The steps are set out in how the annual energy and cost figures are calculated.
The registry lists a maximum flow rate in gallons per minute of 5.8 for the NPE-240S2. That rating and the high draw pattern describe the use behind the 176 therms figure. The figure fits the high-pattern household described above. It does not describe a home whose hot-water demand at the same moment goes above 5.8. For such a home, this data gives no energy figure. It also does not apply to a home without a natural gas supply, because the rating is for natural gas only. The selector by fuel, space and size lists other heater types. A plumber or seller matching this unit can find a same-class replacement by model number within the same 397-model class.
No running cost appears in this text. The cost of 176 therms of natural gas a year depends on the state average residential gas price where the heater runs. For that reason the page computes it from the reader's ZIP. The cost calculator on your own ZIP applies that local rate to this model's figure. The same rate applied to the 182 therms class median shows what the 6 therms gap is worth in that state. The installed-cost range shown elsewhere on this page is a modeled range, not a quote, and carries its own source and date. Energy use at the low or medium draw pattern is not available for this model in this data.
DOE CCD · 2026-09-19