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Space Heater Safety Guide

Written by | Updated November 9, 2020

Space heaters can make a drafty home office feel like a toasty ski lodge. But when left unattended or misused, these appliances become a serious fire hazard.

The good news is that house fires are preventable. By buying a quality space heater and following a few basic safety tips, you can stay comfortable all winter without putting your home at risk.

Space heater safety basics

Types of space heaters

From tiny personal heaters for a chilly office to large outdoor heaters for the garage, space heaters come in a variety of shapes, sizes, and styles.

It’s important to match the power type and size to your need. Propane and carbon-burning space heaters are best left outdoors while electric and oil-filled heaters work well inside.

Indoor space heaters

When you think of space heaters, chances are indoor space heaters come to mind. They can range from personal space heaters small enough for your home office to large units with enough power to warm your living room.

Electric space heaters and oil-filled space heaters can both be used indoors, but some fuel-burning models are best for outdoors or open spaces like your garage or patio.

You’ll come across a few common types of indoor space heaters: portable, radiant, and oil-filled. None of these categories are necessarily safer than others. It all depends on how well you take care of your space heater and how you use it.

The safety features that come with your space heater matter much more than what it’s made of. Look for UL certification, overheat protection, timers, long cords, and tip over shut off.

  • Portable space heaters: A portable space heater is exactly what it sounds like—a small appliance you can carry with you from the home office to the bedroom at night. They’re usually electric with ceramic or quartz heating elements to generate warmth with infrared, convection, or radiant heat.
  • Radiant space heaters: A radiant space heater uses radiant heat with infrared waves to warm you directly instead of the air around you. They can be indoor or outdoor models, mounted to the wall, or attached to wheels. You can even find radiant space heaters shaped like tiny fireplaces to add a homey glow to your living room.
  • Oil-filled space heaters: An oil-filled heater uses thermal convection and radiant heat to warm your space. The oil inside distributes heat evenly through the unit, providing more heat for the room. They’re a cleaner-burning unit than propane or kerosene heaters, making them safe for indoors. Plus, you don’t need to refill the oil inside.

Pick a space heater that fits the room

Aim for a space heater that provides 10 watts per square foot of the room. So if the room is 150 square feet, look for a space heater that produces up to 1,500 watts.

Outdoor space heaters

A propane or kerosene heater is a good solution for a cold garage or back porch in the cold months, but they don’t belong indoors.

Space heaters that burn carbon-based fuels can release dangerous fumes like carbon monoxide, putting your whole household at risk.

These are a few common types of outdoor space heaters:

  • Kerosene heaters: A kerosene heater usually comes with a metal grate around it to prevent accidental touches or tipping over. Because it burns a combustible gas, it’s best left outside. If you love the outdoors, they’re a good addition to your stash of camping supplies.
  • Propane heaters: Like your grill outside, a propane heater uses a tank of propane to generate heat. You can find large or small propane heaters for outdoor use, but they generally cost more than their kerosene-burning cousins.
  • Patio heaters: Patio heaters are best for wide outdoor spaces and flat surfaces like brick or cement. They’re usually tall tower structures that generate heat from burning natural gas through your home’s gas line or a propane tank built into the device.

Camping with a space heater

A space heater can be a great companion for winter outdoor activities. Here’s how to play it safe with these appliances:
  • Do not use fuel-burning space heaters inside tents or cabins.
  • Do not leave your fuel-burning space heater on while you sleep or leave the area.
  • Do not leave flammable material near the space heater.

Setting up your space heater

Your space heater’s location and surroundings can make the difference between a cozy atmosphere and a fire hazard.
According to the National Fire Protection Association, heating equipment is the second leading cause of home fires in the US. On their own, space heaters were the cause of 43% of home heating fires and 85% of home heating fire deaths.1

Here are setup tips for space heaters so you can allot more time for movie night and less time for worrying.

Plug it directly into the wall

Space heaters require a lot of power to generate all that heat. Plug yours directly into the wall for the most secure electrical connection.

Using an extension cord or power strip might feel like a life hack, but we don’t recommend it. A loose connection can start a flame that can spread through your home in minutes.

Watch a loose connection in action

In 2017, the Rossen Report tested space heater mistakes in person. Watch how fast a loose connection connection starts a flame in this demonstration.

Provide at least three feet of clearance

Living rooms and bedrooms are among the most common places for fires to start in the home because of space heaters. So be sure to give yours room to do its job.

Set your portable space heater up at least three feet away from flammable objects like curtains, blankets, upholstery, or furniture. It only takes a few minutes for a blanket to catch fire from a space heater and spread to the couch or curtains.

Create a kid and pet-free zone around the space heater as well. Some models can have hot surfaces that can burn curious kids or pets.

Always place on the floor

When setting up your space heater, you may want to put it on a table, chair, or shelf to bask in the warmth. But even flat surfaces like these aren’t reliable.

We recommend keeping your portable space heater flat on the floor to avoid knocking it over. While many models turn off when they tip over, it’s safest to keep it low to the ground where it can’t fall.

Fire prevention features 

Thankfully, many space heaters have features that minimize fire risks. If you’re shopping for a new space heater, look for ones with these features.

Automatic shut off 

If your space heater falls over, this feature turns it off automatically. This keeps it from scorching your carpet, rug, or anything below it. If you have kids or pets in your house, this is also a helpful feature. Just be sure to keep them far away from the space heater for extra safety.

Overheat detection

Space heaters are designed to get hot, but too much heat can spread to flammable things in your room like bed sheets or curtains (yikes!). Check that your space heater has a thermostat built in so it knows when to cool down.

Timers

Who doesn’t want to go to bed feeling all toasty and warm under the covers? Having a space heater in your room may make it feel more comfortable, but it’s a bad idea to fall asleep with one running if it doesn’t have a timer set.

You can find space heaters with timers as long as 12 hours, but we recommend running it for less time if you can help it.

Energy use and space heaters 

Along with water heating, space heating accounts for nearly two-thirds of home energy use in the US.2 At a whopping 46%, space heating sucked up the most energy from American homes. That’s more than other power drains like air conditioning, lighting, and electronics like TV.

Find the right fit

You wouldn’t use a personal heater for your living room, so why use a giant space heater for a single apartment?

Consider the room you’ll put your space heater in and whether it can distribute heat evenly. We recommend aiming for 10 watts per every 10 square feet to get started.

Use the fan feature 

The fan feature is a common function on many new space heaters. Just like the fan on your air conditioner, this mode distributes heat without using the heating elements.

Run your space heater for a couple hours; then switch it to the fan mode to move the rest of the warm air through the house without using lots of energy.

The most energy efficient space heaters have smart eco modes that use less power to heat your home.

Limit your space heater use

The longer you run the space heater, the more energy it uses. While you might want to keep the heater on all night while you sleep, it’s wasteful and potentially dangerous to leave it on for longer than a few hours.

Some heaters have a built-in timer that will turn off the unit after a certain amount of time. Use your heater to warm the house when you get home; then switch to a more energy-efficient way of staying toasty.

After all, sweaters, cozy blankets, warm socks, and hot cocoa are always en vogue during the winter months.

Space heater FAQ

Is it safe to leave my space heater on while I sleep?

No. Space heaters are already a fire hazard, especially in a small area full of flammable materials like bedding and clothes. Instead, consider an electric blanket with an automatic shut off for your winter hibernation.
If you need a heater while you sleep, look for one with a built-in timer that will turn off after a couple hours.

What makes space heaters so dangerous?

Heat and lots of it. Regardless of your heater’s size or power source, it produces a lot of heat in a short amount of time. All that power can start an electrical fire or spread from a blanket or curtain touching the unit.

What kind of space heater is safest?

The material inside a space heater isn’t as important as its safety features. The safest space heaters are UL certified and have fire-preventative features like overheat protection, automatic shut off, timers, and long cords.

Written by Katie McEntire

Katie McEntire has tested home security systems in her own apartment, installed GPS trackers in her own car, and watched her cat, Toki, nap all day through a live nanny cam feed. As an expert reviewer, she believes that firsthand experience is the best way to learn about new products (even if it requires being the guinea pig). She specializes in pet safety and DIY security and has contributed to publications like DigitalCare.org and TechGuySmartBuy. Learn more

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