NEVER backfeed the electricity into the house.
If done incorrectly, you can electrocute utility workers repairing downed power lines.
For safety's sake, we strongly recommend hiring a licensed electrician to install a power transfer system (starting at $265) to redistribute power from the generator to the circuit panel.
A power transfer system basically contains a manual transfer switch, a power cord and an optional power inlet box. Your type of installation will help you determine if you need the power inlet box and the length of the cord.
If your main electric panel is located in your garage, congratulations. This is the easiest and least expensive way to install a power transfer system.
Your electrician simply connects a manual transfer switch to your main electrical panel. You don't need a power inlet box box since you can run a power cord into the garage.
Always run your generator outside of the garage to prevent carbon monoxide poisoning. You'll need at least a 25-foot power cord to give you ample distance.
If your main panel is located in the basement, you have two options. You can run a power cord through an open basement window.
A better option, however, is to mount a power inlet box on the outside of your house near your electrical panel. The power inlet box is then hardwired directly to your manual transfer switch.
When the power goes out, you simply plug one end of a power cord into the generator. The other end connects to the power inlet box. Flip a few switches, and you're running on backup power.
A typical transfer switch installation will take about 3-4 hours and cost around $200-$300. But it's an investment that will be fully appreciated the next time the power goes out.