A. O. Smith ATI-180B-N 1**
A. O. Smith ATI-180B-N 1** is in the DOE listing as of Oct 26, 2026.
It has a certified UEF of 0.82 and a certified flow of 4.7 gal/min at a 67°F rise.
Its certified flow is 4.7 gal/min at a 67°F rise, while A. O. Smith advertises 10.0 gal/min, no rise stated (Read Oct 4, 2026), so a comparison at the same rise is not possible.
- Gas tankless water heater
- 4 listed models
Not listed as ENERGY STAR certified on Oct 26, 2026.
Certified and advertised figures
- Flow at a 67°F rise
- 4.7gallons per minuteCertified
- Advertised flow
- 10.0gallons per minuteA. O. Smith, no rise stated
- UEF
- 0.82Uniform energy factor
Your fixtures at once
Change your hour and flowFlow where you live
A bigger rise from colder incoming water leaves the heater with less flow.
- Cold water
- Cold water must be at least 10°F colder than the hot water setting.
- Flow estimate
- The estimate uses the lowest certified flow among the listed models. It is about 4.5 gal/min at a 70°F rise.
Flow limits
- The estimate excludes the flow needed to turn the heater on, heat lost in pipes, and installation.
- Cold water from a well or long pipe run can differ from the temperature you enter.
- Without a stated flow limit, estimates for warmer water may exceed the heater’s actual flow.
Advertised and certified figures
| Figure | Advertised | Certified | Advertiser | Read |
|---|---|---|---|---|
| UEF | 0.82 | 0.82 | A. O. Smith | Read Oct 4, 2026 |
| Flow | 10.0 gal/min, no rise stated | 4.7 gal/min at a 67°F rise | A. O. Smith | Read Oct 4, 2026 |
| Flow | 4.7 gal/min at a 67°F rise | 4.7 gal/min at a 67°F rise | A. O. Smith | Read Oct 4, 2026 |
Certified figures by listed model
| Model number | UEF | Flow at a 67°F rise (gal/min) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|
| ATI-180B-N 1** | 0.82 | 4.7 | 84% | High |
| ATI-180X3-N 1** | 0.82 | 4.7 | 84% | High |
| GT12I-180B-N 1** | 0.82 | 4.7 | 84% | High |
| GT15I-180X3-N 1** | 0.82 | 4.7 | 84% | High |
UEF is the uniform energy factor. A dash means the model has no such figure.
It heats 4.7 gallons per minute of water by 67°F in the test. The gas tankless type has a median flow of 4.8 gallons per minute. Its flow at a 67°F rise trails 252 of the 487 gas tankless models.
As of Oct 26, 2026, it was not listed as ENERGY STAR certified. In tests, 82% of the energy it uses ends up as hot water (UEF 0.82). Its test simulated a day of high hot water use (its draw pattern). Of 399 gas tankless models with the same draw pattern, 243 have a higher UEF. For its type and draw pattern, the UEF runs from 0.81 to 0.98. While it heats water, 84% of the energy used goes into the water (its recovery efficiency).
All 4 of its model numbers carry the same certified figures. Its test figures match those of 6 other basic models. They are listed under 6 other brands, one each.
In one state, one rebate program may accept it if it meets their other terms.
Also listed as
They carry every figure in the table above.
Rebates
| Program | State | Status | Program page |
|---|---|---|---|
| SoCalGas High-Efficiency or ENERGY STAR Certified Natural Gas Tankless Water Heaters rebate | CA | May qualify if it meets the other terms | Its own page |
Programs change their terms. Check the program's own page before you buy.
- Every A. O. Smith basic model
- Every gas tankless water heater certified at 4.0 to 4.9 gallons per minute
- Every gas tankless water heater
- The most-searched gas tankless models side by side
Not covered
- Changes to an advertised figure after the date beside it.