How to Hook a Generator to Your Furnace Blower

To heat your house in a power outage, a portable generator can be used to operate the blower to your gas furnace.

Install the Outlet and Plug

But you will have to make some preparations. Usually, your furnace is wired directly to your breaker panel. So you need to break that wiring and install a standard wall outlet to the house side of the wiring, and a plug to the furnace side. Use an outdoor extension cord to get from your furnace to your portable generator.

Shut off the breaker to your furnace.

Cut the wiring and install the outlet to the wiring coming from the breaker panel. Get as close as you can to your furnace. If you are lucky, there will already be a switch there, and you will not need to buy the additional hardware. If you are really lucky, there will already be a plug there.

Install the plug on the furnace side of the wiring.

Plug the furnace in and reset the breaker. Check that the furnace runs properly.

Connect to Your Generator

Place your generator in a safe location outside of the house, with safety considerations like children playing, heat, water and exhaust. Do not put it where it can be flooded or will be in a pool of water. Remember, the exhaust pipe can cause burns.

Run your extension cord from your gas furnace to your generator using an outdoor extension cord.

Plug the extension cord into the outlet on your portable generator. Disconnect the plug from your furnace and plug it into the extension cord.

Start your generator and bring it up to speed. Turn on the output switch on your generator.

Things You Will Need

  • Wall socket and associated hardware
  • Electrical plug
  • Wire
  • Outdoor extension cord


  • Don't wait for the power outage to install your outlet and plug. It will be harder to do with no lights. Do it when you buy your generator or even before.
  • Remember that while your generator is running, you can use it to power other appliances. Just make sure not to overload its capacity.


  • Turn off your breaker before installing your outlet.
  • Never attempt to connect any generator to your house wiring unless you have a professionally installed transfer switch.
  • Do not place your generator inside the house or in a closed garage. It puts out carbon monoxide gas, which can kill you.
  • Use an outdoor extention cord as it is more waterproof and rugged.

About the Author

Richard Asmus was a writer and producer of television commercials in Phoenix, Arizona, and now is retired in Peru. After founding a small telecommunications engineering corporation and visiting 37 countries, Asmus studied broadcasting at Arizona State University and earned his Master of Fine Arts at Brooklyn College in New York.