Radiant SFK 56
Radiant SFK 56 is in the ENERGY STAR list as of Oct 19, 2026.
- Gas tankless water heater
- 1 listed model
No certified figures were found under this model number. Units made for another brand are often certified under that brand's basic model.
Its figures are also listed under Radiant SFK 55.
Certified figures
- Flow at a 67°F rise
- 5.5gallons per minute
- UEF
- 0.95Uniform 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 5.3 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.
Product history
Radiant SFK 56 has a recorded ENERGY STAR market-availability date of Apr 23, 2025. It first appeared in the ENERGY STAR list between March 2025 and June 2025.
ENERGY STAR certified models
| Model number | UEF | Flow at a 67°F rise (gal/min) | Recovery efficiency |
|---|---|---|---|
| SFK 56 | 0.95 | 5.5 | 98% |
It warms 5.5 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. Of 487 gas tankless models, 92 have a higher flow than this one.
The single model number sold under it is ENERGY STAR certified. In tests, 95% of the energy went to hot water, so its UEF is 0.95. Its test ran at the high level of daily hot water use. Its UEF is lower than that of 49 of the 399 gas tankless models with its draw pattern. On its draw pattern, the median gas tankless UEF is 0.93. Of the energy it spends heating water, 98% ends up in it (its recovery efficiency).
Its test figures match those of one other basic model. For the full group, see the Radiant SFK 55 page.
In 7 states, 6 rebate programs may accept it. Another 2 rebate programs 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 | Its own page |
| Colorado Springs Utilities Water heater rebate (gas storage, gas tankless) | CO | May qualify | Its own page |
| Nicor Gas Energy Efficiency Rebates for Your Home (gas tankless) | IL | May qualify if it meets the other terms | Its own page |
| DTE Energy Water Heaters (gas storage, gas tankless) | MI | May qualify | Its own page |
| Xcel Energy MINNESOTA RESIDENTIAL ENERGY EFFICIENCY PROGRAMS (gas storage, gas tankless) | MN | May qualify | Its own page |
| PSE&G Tankless Water Heaters | NJ | May qualify | Its own page |
| Energy Trust of Oregon Residential Incentives | OR, WA | May qualify | Its own page |
| Focus on Energy (gas tankless) | WI | 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 Radiant basic model
- Every gas tankless water heater certified at 5.0 to 5.9 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.