Stay Safe When Using Space Heaters and Wood Stoves

Cold weather, when wood stoves are cranked up and portable electric space heaters are brought out of the basement and plugged in, is when most house fires occur

Enjoying a wood stove on a cold winter day.Photo Credit: Alex Wilson

The morning paper had yet another story about a destructive house fire—fortunately no fatalities (this time*), but the total loss of another home and another family’s belongings. And like many others, the culprit appears to have been the wood stove.

So many of the home fires we experience in Vermont result from trying to keep warm. Some have to do with faulty installation of wood heating equipment; many others result from improper operation of that equipment or management of the ash.

Burning wood safely

Having used a wood stove as a primary heating source for over 30 years, I’m pleased to report that I have never had problem, though evidence in both the house we’re moving out of and our new (old) house shows that other occupants have dealt with fires on multiple occasions. In fact, based on extensive charred wood I’ve found around the chimneys, it’s very lucky that either house is still standing.

There’s a reason that building codes call for specific set-backs from combustible materials and require insulated flue pipe wherever it extends through building components. With any installation of a wood stove, pellet stove, or any other wood-burning equipment, follow manufacturer recommendations carefully to ensure safe operation. (To choose an efficient, clean-burning wood or pellet stove, see our recommended products in GreenSpec.)

On the safe-operation front, a good starting point is to burn only well-seasoned wood. (I admit to a track record that hasn’t always been great in this department.) With dry wood, there will be less need to operate the wood stove with the door ajar an less need to open it up to adjust the logs during operation—both potential risks.

A big part of burning wood is about storing firewood. If, like a lot of people, you have a wood shed for storing the bulk of your wood outdoors and bring in smaller amounts for storage near the wood stove, pay attention to setback from the stove and excessive accumulation of bark and detritus near the wood stove that could catch fire from a wayward ember.

A wood stove installation without the dogs.Photo Credit: Vermont Castings

Managing ashes

Most of the wood-heat-related fires that friends of mine have dealt with have to do not with the wood stove itself, but with ashes. My wife and I store the ashes that we remove from our wood stove in several metal trash cans, and then periodically we scatter those ashes on our garden and fields. We have enough storage that we typically spread the ashes only once a year—in the spring or fall.

An experience last year showed me just how risky spreading ashes can be. I must have run out of ash storage capacity so had to spread some ashes in the spring when we were still using the wood stove. I spread ashes that I had removed from the wood stove weeks earlier, so I hadn’t thought there could possibly be hot coals, but after scattering a number of shovelfuls I noticed some threads of smoke from the grass where ashes had been spread.

I was easily able to deal with the few hot embers using patches of snow that remained on the ground, but it reminded me just how long coals can stay hot when buried in ashes. I’m almost sure those ashes had been in the ash can for at least two weeks.

Other fire risks in cold weather

It isn’t only wood heat that creates a fire risk. Gas- and oil-fired furnaces and boilers can also malfunction, and that happens more commonly in the coldest weather when they are working the hardest.

Cold weather is also when homeowners are likely to use portable electric space heaters. These can overload electrical circuits or result in shorts in the power cord, particularly if the cords are very old or damaged by pets or abrasion. Every year I hear about fires caused by electric space heaters. Examine the cords to those heaters carefully and replace as needed.

In very cold weather we also sometimes hear about homeowners who use a kitchen oven for heat. Whether gas or electric, ovens should never be used for space heating; they aren’t designed for it. When gas ovens (propane or natural gas) are used for space heat, they also introduce combustion products to the house—and all open combustion of gas introduces a lot of water vapor, which can be a problem in some situations. (I actually discourage all open combustion in houses—i.e., gas ranges, cooktops, and ovens—but the indoor air quality issues are much greater when those appliances are used for heating.)

Energy conservation is always safe

Generating heat to create warmth nearly always carries some risk. But reducing the need for supplemental almost never does.

Improved insulation, plugging holes in the building envelope, tightening up leaky windows, and other energy conservation improvements are the best strategies for ensuring safety in houses in cold weather.

Not only are superinsulated houses safer from fire because they require less heat to keep warm, but they are also safer in the event of power outages or interruptions in heating fuel—the resilience argument I’m always making (see Resilient Design: 7 Lessons from Early Adopters). You’ll remain comfortable longer if you can’t operate your heating system, and if you do need to operate a separate space heater, it will be for a shorter period of time.

Safe is good. And conserving energy is the best way to achieve that safety.

* The morning this article came out in our local paper, the front page of that paper had a story of a tragic house fire in my home town of Dummerston in which two people died. No word yet on the cause of the fire, but I suspect it will prove to be heating related.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.