Rinnai IP120S (REB-B3500FFUS)vsWilliamson-Thermoflo FS-80-*
Side-by-side boiler comparison
Rinnai IP120S (REB-B3500FFUS)
AFUE
96%
Fuel
Natural Gas, Propane Gas
Type
Boiler
Hot Water
Can integrate
Williamson-Thermoflo FS-80-*
AFUE
95%
Fuel
Natural Gas, Propane Gas
Type
Boiler
Hot Water
Can integrate
Key differences
Both models are closely matched on afue: 96.0 vs 95.0 %. The Rinnai IP120S (REB-B3500FFUS) is larger at 96 % versus 95 %. Overall, the Rinnai IP120S (REB-B3500FFUS) sits higher in the category, ranking above 93% of certified boilers.
Efficiency
| Spec | Rinnai | Williamson-Thermoflo |
|---|---|---|
| AFUE(%) | 96 | 95 |
| Fuel Type | Natural Gas, Propane Gas | Natural Gas, Propane Gas |
| Can Integrate Hot Water Heating | Yes | Yes |
Configuration
| Spec | Rinnai | Williamson-Thermoflo |
|---|---|---|
| Product Type | Boiler | Boiler |
| Model Name | I-Series Plus | FS-80-* |