7 Dangerous Mistakes You're Making With Your Space Heater

Skipping the Research

Purchasing space heaters that are untested or that lack basic safety features can put you at risk, warns Evan Jones, communications representative for the Electrical Safety Foundation International, a 501(c)(3) nonprofit dedicated exclusively to education on electrical safety.

Always purchase space heaters and other electronic devices that have been listed and approved by a nationally recognized testing laboratory—like UL, ETL, or CSA. “Additionally, look for space heaters that have tip-over protection, automatic shut-off, and overheat protection,” Jones advises.

Utilizing Unsafe Cords

Space heaters draw a significant amount of power, which can easily overload extension cords or power strips not designed for that kind of load. “This can cause the cords to overheat, melt, or even start fires,” warns David Miloshev, HVAC expert and appliance technician with Fantastic Services, a UK-based company of experts that assists with home maintenance matters. “Many people assume a heavy-duty cord is safe, but it still increases the risk of overheating.”

Always plug your space heater directly into a wall outlet. If you must use an extension temporarily, make sure it’s a heavier-rated cord specifically rated for high-current appliances. Even then, Miloshev suggests monitoring the cord temperature and replacing any damaged or worn cords.

Choosing the Wrong Surface

Placing a space heater on a desk, a piece of furniture, or on a thick carpet or rug creates two immediate risks, warns Kristine Pokrandt, agency owner at Goosehead Insurance.

“An unstable surface is more likely to cause the space heater to be tipped over by a pet or if someone bumps into it,” Pokrandt warns. “A soft surface like carpeting can trap heat underneath the unit, causing the fibers or padding to ignite.” 

Instead, always place the heater on a flat, stable, non-flammable surface—like tile or a wood floor. “Placing the unit securely on the ground reduces the chance of tipping,” Pokrandt says, “and using a hard surface prevents heat-trapping that could ignite carpets.”

Using Heaters in Tight or Poorly Ventilated Spaces

Using a space heater in a room or space without proper ventilation can cause overheating. “Similarly, if you’re using a fuel-burning space heater—such as in a garage or on a patio—the poor ventilation can also lead to carbon monoxide buildup in the space, leading to carbon monoxide poisoning,” cautions John Akhoian, founder at Rooter Hero Plumbing & Air. “Even electric heaters can create issues in small rooms with poor airflow, leading to hot spots and increased fire risk.”

Instead, allow plenty of airflow around your space heater. “Never use an outdoor heater indoors,” Akhoian says. “Make sure you have working smoke and carbon monoxide detectors, and clean your heater’s filters or vents regularly for safe operation.”

Leaving Heaters Unattended

Leaving space heaters unattended—especially overnight—can be a big risk. In fact, a quarter of all deaths resulting from space heater fires occur in the early morning hours, warns Jones. “If a problem arises and you’re not there to react immediately, it can result in a serious fire,” he says. 

Even with modern safety features, the risk of overheating, tipping over, or electrical faults increases when no one is awake to respond, says Stephanie Wright, heating and HVAC team at Tractor Supply. “The safest practice is to warm your room before bed,” Wright suggests, “then switch the heater off before turning in for the night.”

Crowding Your Heater

Space heaters can overheat and cause fires when they’re too close to other objects. “Keep space heaters at least three feet from flammable objects, such as paper, clothing, and rugs,” Jones advises. “Never use space heaters for applications other than supplemental heat—including drying clothes, thawing pipes, or warming bedding.”

Lacking Proper Safety Equipment

The proper safety equipment is imperative when operating space heaters in your home. This includes the following:

• Working smoke alarms: "The alarms should be placed on each level of the home, outside of each bedroom, and within each common area such as living rooms, game rooms, and dining rooms," says Stephanie Fox, national spokesperson at American Red Cross. "Ensure you also have a home fire escape plan, which includes two ways to escape each room on each floor and a central meeting location outside of the home, like a neighbor’s house, a tree, or a lamp post."
• Fire extinguisher: The correct fire extinguisher is also a must. "If a fire starts from your heater, that classifies it as an electrical fire," says Jonathan Espinoza from Kord Fire Protection. "Using a regular Class-A extinguisher can make it worse, put yourself in jeopardy, and also further spread the fire instead of extinguishing it." A Class-C fire extinguisher is necessary for electrical fires as these are non-conductive and won't cause an electric shock. 
• Ting sensor: This small, plug-in device monitors the electrical system for micro-arcing, which is a high-frequency electrical signal that travels through your home’s wiring. “This arcing is the earliest sign of a failure in a wire, an outlet, or a connected device like a space heater,” Pokrandt explains. “If your space heater has an internal failure, like a frayed cord, a loose connection, or a failing internal component, it will begin to generate an electrical arcing noise. The Ting sensor detects this noise, analyzes it using its service, and the fire safety team alerts you directly.”