State ATO-180B-N 1**
State ATO-180B-N 1** is in the DOE listing as of Oct 19, 2026.
- Gas tankless water heater
- 2 listed models
Not listed as ENERGY STAR certified on Oct 19, 2026.
Its figures are also listed under A. O. Smith ATO-180B-N 1**.
Certified figures
- Flow at a 67°F rise
- 4.7gallons per minute
- UEF
- 0.82Uniform energy factor
Your fixtures at once
Change your hour and flowFlow where you live
The heater gives less flow when colder incoming water needs a bigger rise.
- 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.
Certified figures by listed model
| Model number | UEF | Flow at a 67°F rise (gal/min) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|
| STO-180B-N 1** | 0.82 | 4.7 | 86% | High |
| STO-180X3-N 1** | 0.82 | 4.7 | 86% | High |
UEF is the uniform energy factor. A dash means the model has no such figure.
It warms 4.7 gallons per minute of water from 58°F to 125°F in the test. The gas tankless type has a median flow of 4.8 gallons per minute. Among 487 gas tankless models, 252 give more flow at a 67°F rise.
As of Oct 19, 2026, it was not listed as ENERGY STAR certified. In tests, 82% of the energy went to hot water, so its UEF is 0.82. Its test simulated a day of high hot water use (its draw pattern). Among 399 gas tankless models on its draw pattern, 243 have a higher UEF. For its type and draw pattern, the median UEF is 0.93. While it heats water, 86% of the energy used goes into the water (its recovery efficiency).
It is the basic model for STO-180B-N 1** and STO-180X3-N 1**. There are 4 more basic models with the same test figures. Each of the 4 other brands lists one of them. For the full group, see the A. O. Smith ATO-180B-N 1**.
It may qualify for one rebate program 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 State 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
- Advertised figures. We have none on file for this model.