Ruud RUTGH-S11I
Ruud RUTGH-S11I is a gas tankless water heater from Ruud rated 5.8 GPM at a 0.96 UEF.
| Uniform Energy Factor (UEF) | 0.96 |
|---|---|
| Annual gas use (natural gas) | 176 therms/yr |
| Recovery efficiency | 98 % |
| Annual propane use | 192.35 gal/yr |
| Fuel | Natural Gas, Propane |
|---|
| Max flow rate | 5.8 GPM |
|---|---|
| Draw pattern | High |
| Minimum activation flow | 0.4 GPM |
| Gas input rate | 199 kBTU/h |
|---|
| Max current draw | 2 A |
|---|---|
| Vent type | Direct Vent |
| Vent size | 2 |
| Smart / connected capable | No |
|---|
| Width | 18.1 in |
|---|---|
| Depth | 13.6 in |
| ENERGY STAR certified | Yes |
|---|
Real flow rate by climate
A tankless heater's usable flow depends on how far it must raise incoming water temperature. Sustained hot-water flow of the Ruud RUTGH-S11I at common temperature rises (a typical shower uses about 2 GPM of mixed water):
| Temperature rise | Climate | Sustained flow | Simultaneous showers |
|---|---|---|---|
| 45 °F | Warm climate (~75 °F groundwater) | 5.8 GPM | 2 |
| 55 °F | Mild climate (~65 °F groundwater) | 5.8 GPM | 2 |
| 70 °F | Cold climate (~50 °F groundwater) | 5.5 GPM | 2 |
| 77 °F | DOE test condition | 5 GPM | 2 |
Similar water heaters
- A. O. Smith ACTH-199M-(N,P) 1 (UEF 0.95)
- A. O. Smith T-H3-OS-N 1 (ACT-199O-N 1) (UEF 0.95)
- A. O. Smith T-H3-OS-N 1 (ACT-199O-P 1-1) (UEF 0.95)
- A. O. Smith T-H3-OS-N 1 (ATO-540H 1) (UEF 0.95)
- A. O. Smith T-H3-OS-N 1 (ATO-540H 1-1) (UEF 0.95)
- A. O. Smith T-H3-OS-N 1 (ATO-540HX3-N 1) (UEF 0.95)
Frequently asked questions
Is the Ruud RUTGH-S11I ENERGY STAR certified?
Yes, the Ruud RUTGH-S11I holds a current ENERGY STAR certification for water heating efficiency (UEF 0.96).
How much does the Ruud RUTGH-S11I cost to run per year?
About $255 per year at national average energy rates, based on its certified annual energy use under the DOE test draw pattern. Your rate and usage change this figure.
What venting does the Ruud RUTGH-S11I use?
The Ruud RUTGH-S11I uses Direct Vent venting with 2 in vent connections. Matching the existing vent type is usually the cheapest replacement path.
Is the Ruud RUTGH-S11I a smart water heater?
No, the Ruud RUTGH-S11I is not connected-capable — it has no app connectivity or demand-response support.
Sources
- data.energystar.gov (retrieved 2026-07-17)