Can a Generator Run a Gas Furnace?


Power outages happen all the time, especially during bad weather like snowstorms. If your power goes out during a cold winter, you will want your furnace to continue running so your house stays warm. It is possible to use a generator to keep a gas furnace running?

A generator can run a gas furnace provided it has enough watts to power your furnace. A transfer switch on the furnace is also required, which must be installed by a professional. Running a gas furnace on a generator is safe as long you follow standard safety precautions when running it.

This article will teach you how to use a generator to run a gas furnace, how safe it is to run a gas furnace with a generator, and how big a generator you will need to run your gas furnace. If you have not bought a generator yet, this article will also give you some options based on price, portability, size, and type of power a generator uses. So, let’s get started!

Is It Safe To Run a Gas Furnace With a Generator?

It is safe to run your gas furnace using a generator as long as you follow the normal precautions when running the generator. The most important safety measure is to keep your generator outside when it is running. 

Generators can release deadly chemicals and gases that are not safe for humans. Even inside, when you keep a room well ventilated by opening windows and doors, generators are not safe to operate. Outside is the best and safest place to have your generator. 

Still, when running a generator outside, use a carbon monoxide detector to ensure none of the deadly gases are entering your home. When you place your generator outside, try placing it as far away from the house as possible. This will help to keep the toxic fumes from entering your house. 

Some generators use gas, like your furnace. If this is the case with your generator, keep extra fuel away from the generator to prevent fires. For battery-powered generators, make sure you always keep your generator fully charged in a safe place, so it is ready to use when you need it.

When you hook up your gas furnace to your generator, use a cord safe for outdoor use and capable of handling all the watts you need to power your furnace. If you are using an extension cord to plug in other appliances in addition to your gas furnace, ensure the extension block is safe to use with multiple cords.

If you have many appliances that you need hooked up to a generator in addition to your furnace, you should consider having two generators. One can run your appliances and one can run your furnace. This will keep your home safe since you are not pushing your generator to run harder than it has to.

How Much Power Do I Need To Run a Gas Furnace?

The amount of power that your generator needs will depend on your furnace’s fan’s horsepower. If you have a gas furnace with a quarter horsepower fan, your furnace will need between one thousand and sixteen hundred watts to start running. Once it gets started, the furnace will need six hundred watts to continue running. A gas furnace with a half horsepower fan will need more than two thousand watts to start and approximately nine hundred watts to keep running.

Most home generators are around five thousand watts which is plenty to power your gas furnace and other appliances that you may need during a power outage. If you only need to power your gas furnace and nothing else, you can get a smaller generator. The benefit to this is that smaller generators weigh less, so they are easy to move. They will also not make as much noise as the larger generators that power multiple appliances.

Keep in mind that you should have a generator that can run a bit more watts than required to accommodate an underestimated amount of watts that your furnace needs. A larger generator will also allow you to run more appliances on your generator in addition to the gas furnace in case of a power outage. 

How Do I Use My Generator To Run a Gas Furnace?

You will need to have a transfer switch installed so you can connect your generator to the furnace. Having a transfer switch is crucial to have before you rewire your furnace to your generator; if you do not have one, a professional will need to install one. 

To avoid electrocution, be sure to turn off your electricity through your breaker before you begin the process. Then, plug the furnace into the generator. Check that the generator and the furnace both work once you rewire and plug the generator into the gas furnace. 

The following video from Prepping Practice will give you more detail on how to power your gas furnace with a generator:

It is advised to practice hooking up your furnace to your generator before disaster strikes. This way, when the time comes, you will know how to do it properly.

Always use the appropriate cords and follow all the safety precautions when you hook up your gas furnace to your generator.

What Generator Is Best for Running My Gas Furnace?

If you do not have a generator yet or are in the market for a new one, below is a lis of the best ones. All these generators will be able to run a gas furnace, depending on size.

  • Small and portable generator: Generac 76711 Portable Inverter Generator. This is a great option for a small generator. It comes in five different sizes ranging from one thousand and two hundred watts up to three thousand and five hundred watts. The generator is small and lightweight, so you can easily transport it when necessary.
  • High power and portable generator: WEN 56475 Portable Generator. This generator comes in two sizes, four thousand seven hundred and fifty watts, and six thousand watts. Each generator comes with a wheel kit, so you can easily transport the generator along with foldable handles. The fuel tank holds four gallons of fuel which will power the generator for up to ten hours.
  • Battery-powered generator: EF ECO FLOW Portable Power Generator. This is a highly rated battery-powered generator. The generator can produce up to eighteen hundred watts of power which you can increase with an extra battery. When you are not using the generator, you can recharge it fully in less than two hours. 
  • Budget-friendly generator: Westinghouse Outdoor Power Generator. This generator is portable, gas-powered, and comes in two different sizes. The fuel tank holds four gallons of fuel which can run for more than thirteen hours, and the generator has additional safety features. 

Final Thoughts

You can run your gas furnace on a generator with no issues, as long as you follow the normal precautions when running your generator and you test them beforehand. You will also need to have a generator large enough to power and run the gas furnace, as well as the proper accessories, such as power cords and fuel.

There are many good generators for sale if you need one to power your gas furnace, including portable and budget-friendly options. Having a generator to run your gas furnace will be crucial for the next time you lose power, especially when there is cold, bad weather. 

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