ELIOS MGWH199IXNN
0.95 UEF DOE CCD · 2026-09-19Grade B: 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, ELIOS MGWH199IXNN uses 178 therms of natural gas a year at the high draw pattern, the standard daily hot-water usage DOE tests against. That is 4 therms below the class median of 182 therms, and its rank is 45th lowest of 397 gas tankless models.
Energy use per year
178 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 45 of 397, lowest energy first.
Solid line: this model (178 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
- 0.95 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
- 5.7 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
- 2026-01-28 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)
- Yes ENERGY STAR · 2026-09-19
What it costs to install
$2,358–$3,405 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
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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 0.95 · Grade B Price it on your ZIP
The figure of 178 therms is calculated by this site, not by the registry. The registry lists a UEF, the ratio of hot water delivered to energy used, of 0.95 for this model. The calculation combines that value with the DOE test's daily hot-water draw for the high draw pattern. The source is DOE CCD, retrieved 2026-09-19. The class median for the same fuel and draw pattern is 182 therms, so this model sits 4 therms below it. The method is set out on the methodology page for annual cost. Actual use in a home is not available from this data, and it depends on how the household's own draw compares with the test draw.
This model is in the lowest quarter of its class for energy use, ranking 45th lowest of 397 gas tankless units registered at the high draw pattern. That comparison suits a larger household, or one where showers and laundry overlap, because the figure was calculated at that draw. The registry lists a maximum flow rate in gallons per minute of 5.7. The energy figure does not show whether that flow covers overlapping demand in a particular home. It does not suit a household with a different draw, since energy use at another draw pattern is not available on this page. To compare other options, use the water heater selector or find a same-class replacement by model number.
Running cost is not stated here because it depends on the state average residential gas price, which differs by reader. The quantity that price applies to is 178 therms of natural gas a year at the high draw pattern. Enter a ZIP in the cost calculator to see the running cost for this model on your own rate. The installed price range appears in its own block with its source and date. It is a modeled range, not a quote, and it is not repeated in this text. The gap of 4 therms from the class median of 182 therms is the only class comparison given here.
DOE CCD · 2026-09-19