When it comes to space heater safety, I’ve always been bothered by a potential contradiction in the advice. On the one hand, safety experts are adamant about the “3-foot rule,” which requires space heaters to be at least that distance from any flammable object, like a curtain or bedspread.
At the same time, a space heater’s power cord is typically 6 feet long. As a result, you can imagine a scenario where the placement of furniture or other large-scale combustibles in the room might make it difficult for a space heater that’s plugged into the wall to stick to the 3-foot rule. In that case, reaching for an extension cord or power strip might seem like a reasonable solution. Wrong!
Here’s why that’s a bad idea: space heaters produce an intense electrical current, with most models from our tests in the Good Housekeeping Home Improvement & Outdoor Lab running at 1,500 watts or more. A standard 15-amp, 120-volt electric outlet in a home can handle that kind of power load. But many light-duty extension cords and power strips are only rated to between 10 and 13 amps, since they’re designed for lamps, phone chargers, and other light electronics. Plugging a space heater into one of these accessories can fry their thin wires, leading to a risk of fire.
That’s why safety experts say you should only plug a space heater directly into a wall outlet. What’s more, you should always unplug the space heater when it’s not in use, since a sudden spike in voltage, whether from a lightning strike or faulty wiring, could cause the device to heat up on its own.
How to play it totally safe
So how do you make the “3-foot” rule work with the “wall outlet only” rule? For starters, you might need to do some minor rearranging of the furniture, so that the bed or sofa is outside of any flammability zones. And remember to always place space heaters on flat, level surfaces, to reduce the chance of them tipping over.
If you’re shopping for a new space heater, it also helps to look for a model that does a solid job distributing heated air throughout the room, maybe with the assist of an oscillating fan. That way, the space heater can be safely positioned away from anything flammable while still keeping the entire space warm and cozy.
Having written thousands of product reviews and how-to articles on all aspects of home ownership, from routine maintenance to major renovations, Dan (he/him) brings more than 20 years of industry experience to his role as the director of the Home Improvement & Outdoor Lab at the Good Housekeeping Institute. A one-time roofer and a serial remodeler, Dan can often be found keeping house at his restored Brooklyn brownstone, where he lives with his wife and kids.
