How to Not Burn Your House Down With a Space Heater | Wirecutter

Updated October 10, 2024

Thom Dunn

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It was the winter of 2019, and I was down in my unfinished basement putting the finishing touches on my band’s next album. I had to get through only a few more guitar overdubs, but my fingers were too cold to play the parts quite right. So I grabbed a space heater I was long-term testing for Wirecutter. I placed it down on top of the wooden workbench where my digital audio workstation was set up and plugged it into the nearest power strip, which just so happened to be the same one through which I ran my half-stack Marshall amplifier.

I turned the heater on. Five seconds later, the power strip blew up.

This might not have been the single dumbest thing I’d ever done in my life. But as I watched the sparks fade from the smoldering lump of freshly burnt plastic before me, I knew it was up there on the list.

According to the Consumer Product Safety Commission, space heaters are involved in more than a thousand home fires every year. The National Fire Protection Association puts that figure into even starker context, noting that space heaters factor into about 46 percent of home heating-related fires (which includes items like water heaters and fireplaces) and 88 percent of associated deaths.

Despite those dire numbers, modern space heaters are actually much safer now than they used to be. “The electric heaters that I grew up with were open element,” said Linda Hotz, former category director for the Home Comfort team at the home appliance maker De’Longhi, in a phone call. “Most heaters today are 100 times better, but ... it still has a heating element, so it isn’t as safe as an air purifier, for example.” Hotz went on to clarify that most home space heaters available today (including our picks) need to be approved by an independent safety testing laboratory such as Intertek (whose certification often appears as an “ETL” seal on the item) or UL. These organizations ensure that heaters have certain safety features built in, such as a thermal shutoff that automatically cuts the power when the heater gets too hot.

But as my amp action demonstrated, nothing is idiot-proof. So here are a few ways to ensure you’re using a heater safely.

It can be tempting to place your space heater somewhere so it blows right in your face. Don’t do that—unless you’re lying flat on the floor, which is the only place your space heater should ever go. Don’t set it on a shelf or a stool or a dusty wooden workbench in the basement. And definitely don’t put it on top of your bed, with all those flammable fabrics and feathery fillings. If at all possible, keep it off the rug, too.

Generally speaking, you should always place your space heater on the flattest, smoothest surface available. Some of our picks, such as the Vornado VH200 and AVH10 are angled slightly upward by default. But you can’t tilt them any further yourself; Like many space heaters come with tip-over switches that make it difficult to tilt them. Even if you can find a way around that, don’t.

This should go without saying, but electricity and water are an even deadlier combination than orange juice and toothpaste. So unless they’re designed and approved for it—and most are not—keep your space heater out of all wet locations such as kitchens or bathrooms. If you want a warm toilet seat, try a bidet.

The CPSC calls it the “3-foot rule,” and it’s pretty simple: Avoid placing a space heater within 3 feet of anything flammable. Some manuals list curtains, papers, furniture, pillows, and bedding as objects to stay away from. The Association of Home Appliance Manufacturers (AHAM) recommends further precautions, such as keeping flammable materials like paint and matches far away. If there’s even a slight risk of a pillow or another flammable object falling, such as in an earthquake, set the space heater somewhere you think that object won’t land on it.

The best way to prevent a fire is to never leave a space heater running in a room unattended—that way, if anything does go wrong, you can take action quickly. If you have kids or pets that could knock a heater over or drape fabric on it, keep a very close eye on its operation. The U.S. Fire Administration recommends keeping children at least 3 feet away from a space heater. We personally don’t leave any space heater in a room or closet within reach of young kids, even if it’s unplugged—beyond the fire risk, a heater is a 15-amp appliance drawing considerable current. The heater’s plug and cord, combined with some intuitive on/off switches, pose a not-so-obvious electrical hazard to a curious toddler. Most kids learn to back away from heat, but very few would anticipate an electric shock.

Many space heaters also come with instructions that warn not to leave them on while you sleep. Several of our picks, such as the De’Longhi TRD40615T, and the Lasko FH500 All Season Comfort Control Tower Fan & Heater in One, come with built-in timers to help you minimize the chance of their running unattended. You can set them to shut off automatically after an hour, for example, so you can fall asleep in a cocoon of hot air without risking an unattended fire. (Oil-filled radiators like the De’Longhi are particularly good for bedrooms because they retain heat for longer and keep emitting warmth after they shut off.)

This is where we start to get into Goldilocks territory. Most modern space heaters should come with enough cord slack that you can plug them into a wall outlet and still position them conveniently in the room for maximum warmth. Notice that we specifically said wall outlet: Manufacturers advise against plugging space heaters into surge protectors, extension cords, plug timers, GFCI outlets (the kind with the test and reset buttons), or really anything that’s not a wall outlet. Those added layers of electrical connection can increase your chances of overloading the circuit, or they can create additional resistance that allows heat to build up, potentially resulting in a fire or other internal electrical damage. Many manufacturers also recommend keeping your space heater a few feet away from the wall where it’s plugged in, to avoid overheating the wall itself. A lot of the picks in our guide fill an entire room with heat, so you should be able to get adequate performance with the heater at a safe distance.

Sometimes, you’ll find yourself with extra cord slack. Or perhaps you need to use a wall outlet in an adjacent room. In situations like these, you should resist the urge to hide the cord from sight as it snakes around the corner. Don’t stuff it under a rug or a couch, as this could prevent heat from escaping. You should also try to avoid pinching or bending the cord, such as passing it through a tightly closed door hinge. That can also impede the electrical current, contributing to a buildup of heat and energy.

As of late 2020, space heaters with built-in smart-home functionality are rare in the United States. But the technology and the regulatory standards are moving quickly, and we’re told to expect more smart space heater tech in the next year or two.

In the meantime, if you need to turn a heater on or off, either remotely or on a schedule, a few of our picks will let you do that. The Lasko FH500 All Season Comfort Control Tower Fan & Heater in One has digital timers built in. Our oil-filled radiator pick, the De’Longhi TRD40615T, has an analog 24-hour dial you can use to set a schedule.

If your space heater lacks a timer—or if you’re just determined to bark heating orders at your voice assistant—consider a plug-in smart outlet. Most space heater manufacturers discourage people from plugging a space heater into an extension cord or surge protector. But a representative of the Wemo outlet’s manufacturer, Belkin, told us in an interview—confirming our interpretation of the product specs—that a plug-in smart outlet should be safe to use with space heaters for up to 15 amps or 1,800 watts of power (most of our picks max out at 1,500 watts). The Belkin rep did add a caveat: “Some space heaters with embedded fans might consume more power and cause a high in-rush current, which could damage or wear out the switching contacts.” So you should be good to go—but remember, don’t turn on a heater remotely without first making sure it’s positioned safely, and don’t leave a heater running unattended.

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