Ruud RTGH-S84I
Ruud RTGH-S84I is in the DOE listing as of Oct 19, 2026. Ruud RTGH-S84I 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-S84I.
Certified figures
- Flow at a 67°F rise
- 4.6gallons per minute
- UEF
- 0.96Uniform 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 4.4 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 | 0.96 | 0.96 | Ruud | Read Oct 5, 2026 |
| Flow | 8.4 gal/min at a 35°F rise | 4.6 gal/min at a 67°F rise | Ruud | Read Oct 5, 2026 |
| Flow | 6.9 gal/min at a 45°F rise | 4.6 gal/min at a 67°F rise | Ruud | Read Oct 5, 2026 |
| Flow | 4.6 gal/min at a 67°F rise | 4.6 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-S84I | 0.96 | 4.6 | 97% | High |
| RUTGH-SR84I | 0.96 | 4.6 | 97% | 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-S84I | 0.96 | 4.6 | 97% |
| RUTGH-SR84I | 0.96 | 4.6 | 97% |
At a 67°F rise, its flow in the test is 4.6 gallons per minute. The median gas tankless model heats 4.8 gallons per minute by 67°F. Of 487 gas tankless models, 300 have a higher flow than this one.
All 2 of its model numbers are ENERGY STAR certified. In the test, 4% of its energy does not reach the hot water (UEF 0.96). In the test, daily hot water use was set to high (its draw pattern). Among 399 gas tankless models on its draw pattern, 15 have a higher UEF. For its type and draw pattern, the median UEF is 0.93. Of the energy it spends heating water, 97% ends up in it (its recovery efficiency).
It is sold as RUTGH-S84I and RUTGH-SR84I. All of its test figures are shared by 3 other basic models. The Friedrich, Rheem, and Richmond brands list one or more of them. You can find the whole group on the page for the Rheem RTGH-S84I.
In 7 states, 6 rebate programs may accept it. It may qualify for 2 more 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 | 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 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.