Using Your Furnace During A Power Outage

by Evan on May 17, 2010

David Morris here with this weeks Urban Survival Newsletter.

One of the big problems that houses in colder climates have is that they don’t have wood fireplaces and their heating systems require electricity to work. Gas furnaces require electricity to run the blower and thermostat, and even most pellet stoves require electricity to run the auger. It’s not uncommon to find whole neighborhoods of houses with gas furnaces, gas fire places, lots of windows, and no backup if the electricity goes out.

As many people find out every winter, this means is that in a power outage, you might have all the fuel you could want to heat your home, but still not be able to. As I’ve talked about in other articles, you can keep yourself warm enough by dressing warmly, creating a shelter within your house, and using the fuel you have to heat liquids to drink. That being said, you may still need to keep your house above freezing to protect your plumbing.

Keep in mind that the strategy that I use may not work for you. In many cases, electrical work must be done to code by a licensed electrician for your homeowners’ insurance to remain valid. This is serious stuff. It could kill you or loved ones, or cause your house to burn to the ground with no possibility of a check from your insurance company. Don’t screw around with this stuff…get a licensed electrician to help you. Even then, this method may not be up to code for your area and it might require serious modification to be legal and safe.
In short, what you do is add an outlet and a plug to your furnace (instead of running straight to your circuit panel), get a long heavy extension cord, that will run from your furnace to your car, a properly sized inverter for your car, and extra gas.

Just to clarify, an inverter takes the 12V DC power from your cigarette lighter and turns it into 120V AC power that will power your furnace blower.

This is obviously an UGLY solution, and won’t work in many apartments or condos, but it IS a field expedient way to heat your house when you’ve got fuel but no electricity.

Since it’s very modular, there are several benefits to implementing this strategy, namely:
1.    It’s fast and inexpensive to implement. $100-$400 for the inverter, and very little else if you have a friend who’s an electrician.

2.    You can easily upgrade from using your car’s alternator to using a generator.

3.    It’s another good reason to have extra fuel on hand.

4.    An inverter has all sorts of benefits in a survival situation, from converting solar power to 120V, powering computers, running other appliances from your automobile, and charging batteries that you only have wall chargers for. In the meantime, you can use it on road trips, for camping, and more.

Here are some “gotchas” that you’re going to want to look out for:

1.    You’ll notice that there is no connection between the inverter and the electrical panel or double-male plugs in this setup. It is designed to power one appliance at a time. If you want to get tricky and do more, have an electrician set it up for you.

2.    Your alternator may not put out enough amperage at warm idle to power your inverter. Check the specs on your alternator (It’s very unlikely that they’ll be easy to find), have a mechanic test the output of your alternator at warm idle, or shine your headlights at a wall with the engine idling, plug in your inverter, and plug in your furnace or some other appliances. If your headlights get dimmer and stay dimmer, then the alternator on your car isn’t big enough to power your inverter and you need to try a different vehicle, increase the idle speed of your car (which will run through gas quicker), or upgrade the alternator in your car. A beefed up alternator will put out more amperage at lower RPMs, but will also cost you $100-$300 more.

3.    You need to make sure that your inverter is sized correctly to handle both the run load of your furnace blower and the peak load when it starts up. As an example, if the run load of your furnace is 2.3 amps, the peak load might be 6.5 amps.

4.    You need to make sure that you have a HEAVY, rated extension cord that’s rated for the length and current load that you’ll be using.

5.    Make sure that you have a licensed electrician set up the plug/outlet to local code.

One of the beautiful things about this mini-project is that you can go out and buy your inverter, extra gas, and extension cord TODAY. Even if you never get the interface with your furnace set up, you’ll still be able to benefit from the extra gas and the inverter. Still, I’d get on the phone and call an electrician to schedule a time to have them come over and get your furnace(s) set up right away.

What do you think about this strategy/mini-project? Let me know by commenting below:

While you’re there, check out some of the other recent articles, including:
“Friends, Families, & Bubbas” by BNMLuedeman. He talks about one of the topics from the SurviveInPlace Urban Survival Course…why it’s smart to be friends with “bubbas.” You can read the whole article by going here:

And “Integrator” wrote a great piece on “What To Do After Using Deadly Force to Defend Yourself.” You can see it here:

Make sure to go on over to and pick up a deck for each go-bag and vehicle you own, as well as for relatives. They contain 52 urban survival snippets from the Urban Survival Course that you can use when you’re under stress to survive disasters ranging from earthquakes, blizzards, and tsunamis to full fledged breakdowns in civil order.

Until Next Week,

David Morris

P.S. If you haven’t signed up for the Urban Survival Course, you really should. It goes into much more detail on powering electronics in a “grid down” situation, how to secure generators, and 12+ weeks of proven techniques to survive disasters in urban environments.
Sign up now by going to:

P.P.S. What do you mean by “Urban?” Great question…urban can range from small cities to metropolises, but the most basic definition for this course is ANY area where housing is dense enough to warrant municipal water, sewer, and/or gas…in other words, it covers where you live..

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