Generac Guardian Series 5525 20,000 Watt Air-Cooled Propane/Natural Gas Powered Home Automatic Standby Generator with Aluminum Enclosure (Discontinued by Manufacturer) Convenient, hands-free operation with no fueling. No manual start. No extension cords. Runs on natural gas or liquid propane. Clean, smooth True Power Technology provides safe operation of sensitive electronics. Patented Quiet-Test low speed exercise mode Does not include transfer switch 20,000 Rated Watts. CARB Compliant.