The tiny radiators, while useful, cause thousands of fires and hundreds of deaths each year. Here are some tips to stay safe while you stay warm.
By Thom Dunn
(Mr. Dunn is a staff writer at Wirecutter, a product recommendation site owned by The New York Times Company.)
One day last winter, I was down in my unfinished basement working on some music, and my fingers were too cold to play the guitar. So I grabbed a space heater that I was long-term testing for Wirecutter, placed it on the wooden workbench where my audio workstation was set up, and plugged it into the nearest power strip — the one my Marshall amplifier was also plugged into. I turned the heater on and waited five seconds. The power strip blew up. It might not have been the dumbest thing I’d ever done, but as I watched the sparks fade from the smoldering lump of burned plastic, I knew it was high on the list.
According to the U.S. Consumer Product Safety Commission, an estimated 25,000 residential fires are associated with the use of space heaters every year, causing more than 300 deaths and 6,000 trips to the emergency room. Despite the frightening numbers, though, 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, category director for the Home Comfort team at the home appliance maker De’Longhi. “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.”
While electric, radiant, or convection heating is typically safer and more efficient than a combustion heating system, heat production still requires heat, which always carries risks. Fortunately, space-heater designs now have better insulation around the heating coils and smaller grates to prevent curious fingers from finding their way inside. Many modern space heaters — including those recommended by Wirecutter — also have an automatic shut-off that cuts the power when the device reaches a certain temperature, and a sensor to detect a blocked air passage that could cause heat to build up. Some have tip-over switches that shut down the heater if it’s not flat on the ground.
As Ms. Hotz noted, most home space heaters must now be approved by an independent safety testing laboratory, such as Intertek (whose certification often appears as an “ETL” seal on the item) or UL. But as I demonstrated in my basement, nothing is idiot-proof. So here are a few ways to ensure you’re using a heater safely.
The Heater Belongs on the Floor
It may 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 just about the only place it should ever go. Don’t set it on a shelf or a stool or a wooden workbench in the basement. If possible, keep it off the rug, too, and definitely off your bed. While these scenarios might appear safe, they increase the risk of the heater falling, tipping over or otherwise overheating, which could start a fire.
To avoid that, we generally recommend placing your space heater on the flattest, smoothest surface available. Some of Wirecutter’s picks, including the Vornado VHEAT Vintage Heater, let you tilt the heating element upward; the Vornado VH200 and AVH10 are angled slightly upward by default, but you can’t tilt them any further. Don’t try to find a way around that.
Keep It Away From Water
This should go without saying, but electricity and water are an even deadlier combination than orange juice and toothpaste. Keep your space heater out of kitchens and bathrooms.
Avoid Flammable Objects, Too
The Consumer Product Safety Commission calls it the “three-foot rule,” and it’s pretty simple: Avoid placing a space heater within three 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 recommends further precautions, including 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 the object won’t land on it.
Never Leave the Heater Alone
The best way to prevent a fire is to never leave a space heater running unattended. If you have children or pets that could knock over a heater or drape fabric on it, keep a close eye on its operation. The U.S. Fire Administration recommends keeping young children at least three feet from a space heater, but it’s best not to leave one in a room or closet within reach of children, even if it’s unplugged — beyond the fire risk, the heater is a 15-amp appliance drawing considerable current. The plug and cord, combined with some intuitive on/off switches, pose a hazard to a curious toddler who won’t be anticipating an electric shock.
The instructions with many space heaters also warn not to leave them on while you sleep. Several of Wirecutter’s favorites, such as the De’Longhi TRD40615T, and the Lasko FH500 All Season Comfort Control Tower Fan & Heater in One, come with timers to minimize the chance of their running unattended. (Oil-filled radiators like the De’Longhi are particularly good for bedrooms because they retain heat for longer and continue emitting warmth after they shut off.)
It Wants to Be in a Wall Outlet
Most modern space heaters should come with enough cord slack to allow you to plug them into a wall outlet and still position them conveniently in the room for maximum warmth. Notice that we said wall outlet: Manufacturers advise against plugging space heaters into surge protectors, extension cords, plug timers, G.F.C.I. outlets (the kind with the test and reset buttons) — anything that’s not a wall outlet. Those added layers of electrical connection can overload the circuit, or create additional resistance that allows heat to build up, potentially resulting in a fire or 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 Wirecutter’s guide fill an entire room with heat, so you should be able to get adequate performance with the heater at a safe distance.
If you find yourself with extra cord slack, or you need to use a wall outlet in an adjacent room, resist the urge to hide the cord from sight. Don’t stuff it under a rug or a couch, which could prevent heat from escaping. Also avoid pinching or bending the cord, such as passing it through a tightly closed door hinge, which can impede the electrical current, contributing to a buildup of heat and energy.
How to Add Smart Controls
Space heaters with smart-home functionality are rare in the United States. But the technology and the regulatory standards are moving quickly, and we can expect more smart space-heater tech in the next year or two.
In the meantime, if you want use a heater remotely or on a schedule, a few of Wirecutter’s picks can do that. The Lasko FH500 All Season Comfort Control Tower Fan & Heater in One, and the Vornado OSCTH1 have digital timers built in. Wirecutter’s 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 like the Wemo Mini. Although most manufacturers discourage plugging a space heater into an extension cord or surge protector, a representative of the Wemo outlet’s manufacturer, Belkin, said in an interview — confirming Wirecutter’s interpretation of the product specs, as well as our tests — that a Wemo Mini should be safe to use with space heaters for up to 15 amps or 1,800 watts of power. Most of Wirecutter’s picks max out at 1,500 watts. But not all heaters are the same, and the Belkin representative did add a caveat: “Some space heaters with embedded fans might consume more power and cause a high inrush 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 without first making sure it’s positioned safely, and don’t leave it running unattended.