Can You Run A Furnace On A Generator: Hot Facts and Important Issues

When the power goes out, it’s alarming, but having a generator makes it less stressful, but how much can you run with one generator? Can you run a furnace on a generator? When you’re new to the world of generators, it all seems confusing and complex, but they’re easier to work with than you might think. in most cases, it’s a simple matter of power, ‘plug and play.’ In short, your generator needs either a battery or gas power source that’s working, and then you plug things into it with the available sockets. Always check to see if a generator has outlets in the style you need, or get an appropriate converter to go along with it. The other important issue is having a large enough generator to handle your furnace. Fortunately, most gas furnaces run on a fairly small wattage. I will share everything you need to know to hook your generator to your furnace safely so you can stay warm when the power goes out. 

Can you run a furnace on a generator? You can run a furnace on a generator. Unlike air conditioners, a gas furnace often uses a more modest amount of energy, around six hundred watts, though this will vary by model and size. When it’s cold, hooking your furnace into your generator can be a real lifesaver, so it’s always worth keeping one around in case of emergencies. 

What Size of Generator Do I Need To Run a Furnace

Since you can run a whole house with the right generator, it’s a given that you can also run a furnace. However, generators and furnaces both come in a variety of sizes. The trick is finding compatible devices. Fortunately, it’s not that difficult. 

Many homes have small gas furnaces. Better still, these furnaces don’t require a lot of power to run. According to Mosby Building Arts, “Most gas heat furnaces use less than 600 watts of electricity or less than half of a typical 15 amp electric circuit.”

If you are running a small, portable generator, this means you cannot run everything in the house at once. Then again, few people decide they need to microwave food, watch three TVs, and vacuum while the main power is out. So long as you are using your generator to power emergency necessities like your furnace, some lights, and cooking equipment, you will be just fine.

Run your small furnace with a WEN 56203i Portable Inverter Generator from Amazon. This model is very quiet, according to the US Department of Health and Human Services. Moreover, this easy-to-move generator puts out two-thousand surge watts and seventeen-hundred rated watts of power. You get one 12V DC receptacle, two three-prong 120V receptacles, and two 5V USB ports. Best of all, your new WEN generator has a one-year warranty included. Learn more on Amazon by clicking here. 

What Size Of Generator To Run Hot Water Heater

You can run more than a furnace on a generator. For example, a water heater can shower and do dishes, a basic necessity no one wants to go without. Unlike a small furnace, a water heater uses a bit more power. 

Normally a water heater requires about four thousand watts of power. Hence, it would be best to have a generator that runs a minimum of four thousand watts. That’s a large amount for a portable generator, though they certainly exist. 

When choosing a generator for your water heater, you need to look at two different numbers. Regrettably, too many people only notice the peak or surge watts power rating and assume this is how much power it will have at all times. This is not the case. 

It would be smart to pay close attention to the running watts. This is the number that will show you how much power output is average for your machine. In the case of water heaters, they account for almost twenty-five percent of a home’s energy use. 

You will need a four-thousand-watt running generator merely to power that water heater. There are three ways to handle this issue. Either you can use a large generator, opt for two separate generators, or install a heat-on-demand, low energy water heater. 

Obviously, a big generator is an easy solution. Likewise, hooking up a generator that only handles your hot water means powering it on before using water and turning it off again when you finish, thus conserving fuel. However, using a low-energy water heater that only heats what you need instead of constantly running will save you money in the long run. 

Will a Generator Damage My Furnace

Asking whether you can run a furnace with a generator and knowing whether you should are two very different issues. I wish I could say you can plug in with impunity, but that is not the case. Certainly, in an emergency, when you’re freezing, a working furnace can save your life quite literally. Sadly, it could cost you in the long run. 

Generators run what is known as ‘dirty power.’ This doesn’t mean that the power itself is somehow polluted, but it does mean that there are abnormalities in the power supply. For example, you may notice frequency and voltage variations or surges.

The good news is that, when used rarely, it shouldn’t be a problem. However, these changes in the power supply will wear on your furnace and other electrical equipment over time. It’s best to use a generator only when you absolutely need it to avoid long-term damage to your furnace and other appliances. 

I recommend a Durostar DS4000S Portable Generator because it can handle up to thirty-three-hundred watts. That’s enough for a larger furnace to stay warm. Better still, a DS4000S is EPA and CARB approved for use in all fifty states. You get an oil funnel, sparkplug wrench, manual, and toolset to keep your generator running right. See the outstanding Amazon ratings by clicking right here. 

Will a 12000-Watt Generator Run a House

Naturally, people want to run more than one furnace with a generator when the power is out. How large should your generator be? Will a twelve-thousand-watt generator run a house?

The answer will depend on the size of your home and how much power it requires. That said, yes, a twelve-thousand-watt generator will handle most of a normal household’s needs. You should be able to run lights, cook, heat your home, and turn on other devices. 

Moreover, it’s notable that many generators run better when there’s more than one item using power. Though this doesn’t mean you should turn on everything in the house, it does mean it’s safe to run your coffee pot, cook a meal with the lights on and even run that furnace. 

To run basic, essential household electronics, you typically need a generator that can handle three to seventy-five hundred watts. If you live in an RV, then you may not need anything larger. As homes go up in size and the number of plugged-in appliances, the power needs increase. 

Choose your generator based on your specific needs. To calculate how much power you run, you can look at the wattage on all of your devices. This includes lightbulbs and air conditioners. Fortunately, you’ll rarely, if ever, need to turn on everything at once, even in an emergency. 

Will a 10000-Watt Generator Run Central Air

Like your furnace, central air will run on a generator. However, an air conditioner requires a substantially larger amount of power. That’s why your electricity bill likely goes up during the hottest part of the year. 

For most AC, you will need a minimum of ten thousand watts. So, a ten-thousand-watt generator will un your air, but it might not be able to handle much beyond that. Interestingly, an energy-efficient system will almost certainly use slightly less power, but it won’t make a huge difference. 

When you need to run the air, you have a smallish generator, then turn it off and unplug other devices and appliances while you cool your home. When looking at essential appliances, an air conditioner is considered a luxury. 

The Westinghouse WGen3600v Portable Generator from Amazon has an automatic low-oil shutoff to prevent damage. At thirteen and a half hours of run time per tank, you’ll have a functional furnace all day. With minimal setup and a manual, so you can get started, you’ll have that furnace running in no time. Have Amazon deliver to your door by clicking here. 

Final Thoughts


Staying warm is no joke when temperatures drop. Unfortunately, far too many people are unprepared for extreme weather, even though it happens all the time and no one is exempt. It would be best if you had a portable home generator for your furnace and other vital systems.

Hooking up a generator is fairly straightforward, and anyone can learn to do it correctly. So long as your generator has enough watts, a power source, and things are plugged in correctly; you should get the energy you need to stay warm. However, it’s important to store a generator properly and do regular maintenance. 

As life-saving equipment goes, a generator is near the top of the list. When things go dark, you can complain and freeze, or you can plug in that generator and stay warm. The choice is up to you. 

Aron Blake

I am the lead copywriter on Homezesty and the Webmaster. I have a lot of experience in home renovations and the creation of style. I enjoy writing and sharing my tips on how to create the best living environment. My Linkedin Profile, My Twitter Account

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