Ruud RTGH-S10I
Ruud RTGH-S10I is in the DOE listing as of Oct 19, 2026. Ruud RTGH-S10I is in the ENERGY STAR list as of Oct 19, 2026.
- Gas tankless water heater
- 2 listed models
Its figures are also listed under Rheem RTGH-S10I.
Certified figures
- Flow at a 67°F rise
- 5.2gallons per minute
- UEF
- 0.96Uniform 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 5.0 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 |
|---|---|---|---|---|
| Flow | 10.1 gal/min at a 35°F rise | 5.2 gal/min at a 67°F rise | Ruud | Read Oct 5, 2026 |
| Flow | 7.9 gal/min at a 45°F rise | 5.2 gal/min at a 67°F rise | Ruud | Read Oct 5, 2026 |
| Flow | 5.3 gal/min at a 67°F rise | 5.2 gal/min at a 67°F rise | Ruud | Read Oct 5, 2026 |
Certified figures by listed model
| Model number | UEF | Flow at a 67°F rise (gal/min) | Recovery efficiency | Draw pattern |
|---|---|---|---|---|
| RUTGH-S10I | 0.96 | 5.2 | 98% | High |
| RUTGH-SR10I | 0.96 | 5.2 | 98% | High |
UEF is the uniform energy factor. A dash means the model has no such figure.
ENERGY STAR certified models
| Model number | UEF | Flow at a 67°F rise (gal/min) | Recovery efficiency |
|---|---|---|---|
| RUTGH-S10I | 0.96 | 5.2 | 98% |
| RUTGH-SR10I | 0.96 | 5.2 | 98% |
It heats 5.2 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. Among 487 gas tankless models, 145 give more flow at a 67°F rise.
All 2 of its model numbers are ENERGY STAR certified. In tests, 96% of the energy it uses ends up as hot water (UEF 0.96). Its test ran at the high level of daily hot water use. Of 399 gas tankless models with the same draw pattern, 15 have a higher UEF and 350 a lower one. For its type and draw pattern, the median UEF is 0.93. When it runs, 98% of the energy it uses reaches the water (its recovery efficiency).
It is sold as RUTGH-S10I and RUTGH-SR10I. There are 3 more basic models with the same test figures. Of those, one or more are under the Friedrich, Rheem, and Richmond brands. For the full group, see the Rheem RTGH-S10I page.
It may qualify for 6 rebate programs in 7 states. 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 Ruud 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
- Changes to an advertised figure after the date beside it.