How to safely use a space heater

Those bunny slippers are dangerously close to the space heater. They should be at least 3 feet away.
Shutterstock / Dennis Cox
Those bunny slippers are dangerously close to the space heater. They should be at least 3 feet away.

The cooler temperatures are officially here, and if you haven’t turned on the heat already, you’ve probably at least considered it. If your house lacks adequate heating, if you’re one of the thousands currently without gas heat in the Merrimack Valley, or if you just need a little extra warmth in certain places in your home, a portable space heater might be your go-to device.

Use of space heaters is common, but they also account for “vast amounts of civilian deaths and injuries,” according to Boston Fire Marshal Jack Dempsey, who is also deputy chief of the Boston Fire Department.

“The leading factor contributing to ignition of home heating fire death is heating equipment too close to flammable items,” Dempsey said. “Like upholstered furniture, clothing, mattresses, or bedding.”


“One of the other things that I’ve seen over the years is some people will try to use [space heaters] to dry a towel or clothing,” Dempsey said. “I’ve actually been at a fatality where the woman had a towel on it, trying to dry it, and it caught fire.”

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But Dempsey said there are simple tips that can help people use space heaters safely.

According to Dempsey, if people already own a space heater, they should check to make sure that it’s not too old or damaged. (Frayed wires are a red flag.) Newer space heaters almost always come with an automatic shut off, which cuts power if the heater tips over.

Before buying a space heater, consumers should check to make sure that its UL listed. UL, or the Underwriters Laboratories, is a well-respected organization that tests products against their safety regulations. Dempsey also advised that almost all kinds of space heaters should be installed by a professional licensed in the product.

“The other thing is, space heaters should not be used as your number one source of heat,” Dempsey said. While the space heater “is fine for taking the edge off if you’re in the room,” it shouldn’t be used to heat an entire home or left on overnight or while no one is home. Dempsey strongly suggested reaching out to a landlord or property manager to see if they can increase the output of heat before relying on a space heater.


To avoid fires, flammable items should be at least three feet away from the space heater, Dempsey said. The same goes for children and pets, who will be unaware of the dangers or mechanics of portable heaters. 

“Kind of tough to keep a cat or something or a dog away, because they like the heat,” Dempsey said, “but whatever you can do.” Since animals “are apt to knock it over,” Dempsey again stressed the importance of having a heater with an automatic shut off.

The same goes for extension cords. Space heaters shouldn’t be used with an extension cord, but if using one is necessary, make sure it’s UL listed, heavy duty, and has an automatic shut off. 

Dempsey referenced the National Fire Protection Association, which released new research this year, stating, most alarmingly, that 43 percent of home heating fires in the country can be attributed to space heaters, and that they account for 85 percent of home heating fire deaths. 

Like Dempsey, the NFPA also cautioned against leaving anything flammable too close to a space heater, as that accounted for more than half of the home heating fire deaths.


“Some of these things seem so simple,” Dempsey said, “but people really will overlook that.”

Lillian Brown can be reached at Follow her on Twitter @lilliangbrown.