Westinghouse HS120
Westinghouse HS120 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 Fogatti FDG-CS120S.
Certified and advertised figures
- Flow at a 67°F rise
- 2.9–3.3gallons per minuteCertified
- Advertised flow
- 5.1gallons per minuteLowe's, up to, no rise stated
- UEF
- 0.82–0.83Uniform energy factor
The 2 listed models differ. A range runs from the lowest figure to the highest.
Your fixtures at once
Change your hour and flowFlow where you live
Colder incoming water needs a bigger rise, so the heater gives 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 2.8 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 | up to 0.81 | 0.82 | Lowe's | Archived copy, Aug 30, 2025 |
| Flow | 5.1 gal/min, no rise stated | 2.9 gal/min at a 67°F rise | Lowe's | Archived copy, Aug 30, 2025 |
| Flow | up to 5.1 gal/min, no rise stated | 2.9 gal/min at a 67°F rise | Lowe's | Archived copy, Aug 30, 2025 |
Certified figures by listed model
| Model number | UEF | Flow at a 67°F rise (gal/min) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|
| HS120A1G-LP | 0.83 | 3.3 | 85% | Medium |
| HS120A1G-NG | 0.82 | 2.9 | 82% | Medium |
UEF is the uniform energy factor. A dash means the model has no such figure.
Its flow at a 67°F rise is 2.9 to 3.3 gallons per minute, by model number. The median flow among gas tankless models is 4.8 gallons per minute. Its flow at a 67°F rise trails 451 of the 487 gas tankless models.
On Oct 19, 2026, this heater was not listed as ENERGY STAR certified. Its listed models turn 82 to 83% of the energy used into hot water (UEF 0.82 to 0.83). Its test ran at the medium level of daily hot water use. Of 77 gas tankless models with the same draw pattern, 26 have a higher UEF. A UEF of 0.82 is the median for its type and draw pattern.
It is sold as HS120A1G-LP and HS120A1G-NG. All of its test figures are shared by 2 other basic models. The Fogatti and Mizudo brands list one or more of them. For the full group, see the Fogatti FDG-CS120S.
It may qualify for one rebate program if it meets terms its figures do not show.
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 Westinghouse basic model
- Every gas tankless water heater certified below 4.0 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.