Standby generators offer a steadfast solution to extended outages. Unlike portable generators, they’re installed permanently on a concrete pad in your yard and will provide uninterrupted back up for days, because they’re connected directly to your home’s electrical panel and powered by an external fuel supply, such as natural gas, liquid propane, or diesel. Smaller, air-cooled essential-circuit units (below) are slightly larger than portable generators ad can energize just a few circuits at a time. Larger, liquid-cooled whole -house systems will do just as their name suggests-they’ll comfortably power an entire home. The brains behind the operation is an automatic transfer switch that disconnects you from your utility after detecting an interruption in service. Once your home is safely off the grid, the switch starts up the generator before transferring its power to the home’s electrical panel. At the heart of the system is an internal combustion engine, which is usually fueled by the local natural gas company. Where natural gas isn’t available, liquid propane or diesel stored in large tank nearby can be used.