Space Heater Safety: When to Use One and When to Fix the Heat Instead

Quick answer: Electric space heaters can be used safely if you keep them at least three feet from anything that can burn, plug them directly into a wall outlet (never an extension cord), choose models with tip-over and overheat shut-off and never leave them running unattended or while you sleep. Never heat your home with fuel-burning heaters, grills, ovens or generators, because they produce carbon monoxide. And if you need a space heater every day to stay warm, the real problem is usually your heating system, ducts or insulation, which we can fix with heating repair.

Every winter, space heaters come out of closets across New Jersey. Used carefully, they help warm a chilly room. Used carelessly, they are a leading cause of home heating fires. This guide covers how to use them safely, what they cost to run and how to tell when the real fix is your central heat.

The safety rules that matter most

1. Three feet of clearance from curtains, bedding, furniture, papers, clothing and anything else that can burn
2. Plug directly into a wall outlet, never into an extension cord or power strip, which can overheat
3. Never leave it running unattended, and turn it off when you leave the room or go to sleep
4. Use models with tip-over and overheat shut-off and a recognized safety certification label
5. Place it on a hard, level, non-flammable floor, not on a rug, bed or furniture
6. Keep children and pets away
7. Inspect the cord and plug; stop using any heater with a damaged cord or that smells hot
8. Do not use it in bathrooms or wet areas unless it is designed for that

Fuel-burning heaters and carbon monoxide

Kerosene, propane and other unvented fuel-burning heaters release combustion gases, including carbon monoxide (CO), into the room. CO has no color or smell and can cause headaches, dizziness, nausea, confusion and death. Many such heaters are not intended for indoor living spaces at all.

Never use these to heat your home:

• Gas ovens or stovetops
• Charcoal or gas grills
• Camp heaters
• Portable generators (never indoors, in a garage or near windows)

Make sure every level of your home has a working CO alarm, and test it monthly. See carbon monoxide and furnace safety.

Choosing a safer space heater

• Oil-filled radiators stay warm and have no exposed hot element, but they are heavy and slow to heat
• Ceramic heaters heat quickly and often have good safety features
• Infrared heaters warm people and objects directly
• Look for tip-over shut-off, overheat protection, a cool-touch exterior and a thermostat

Bigger is not better: an oversized heater in a small room just cycles on and off and wastes electricity.

What do space heaters cost to run?

A typical plug-in electric heater uses about 1,500 watts on high. Running it for long periods, especially in several rooms, adds up quickly on your electric bill. For comparison, a modern heat pump delivers far more heat per unit of electricity than a space heater, because it moves heat rather than creating it, and a gas furnace or boiler heats the whole home more economically than multiple plug-in heaters. Check the wattage on your heater and your electric rate to estimate your own cost. See ways to lower heating bills.

When a space heater makes sense

• Short-term warmth in a small room for an hour or two
• A room you rarely use, such as a guest room or hobby space
• While waiting for a repair when your heat is out (see no heat in freezing weather)
• Taking the chill off a home office in the morning

When it is a sign of a bigger problem

If you rely on space heaters every day, something is wrong with how heat reaches that room. Common causes:

• Closed, blocked or poorly placed vents
• Leaky or crushed ductwork in attics, crawl spaces or garages (see duct sealing)
• No return air in the room, so warm air cannot flow in
• Undersized ducts to rooms added later, such as additions or bonus rooms
• Poor insulation or drafty windows
• An aging or undersized furnace or boiler
• Cold radiators that need bleeding or balancing (see cold radiators)
• A thermostat in the wrong location

See uneven temperatures and cold rooms.

Better long-term fixes than a space heater

• Duct sealing and balancing so heated air actually reaches the room
• Adding a return in rooms that feel stuffy or cold
• Zoning so the room has its own thermostat (see HVAC zoning)
• A ductless mini-split for additions, sunrooms, finished attics and basements (see mini-split guide)
• A properly sized new furnace, boiler or heat pump if the system is old or undersized
• Insulation and air sealing

Space heaters and older homes

Older homes often have limited electrical circuits. Running a 1,500-watt heater on a circuit that already powers other appliances can trip breakers or overheat wiring. If lights dim or breakers trip when the heater runs, stop using it on that circuit and have an electrician check the wiring.

Space heaters during an outage

During a power outage, electric space heaters will not work, and portable generators must stay outdoors, far from doors and windows. If your heat is out in freezing weather, protect your pipes, dress warmly, gather in one room and call for emergency heating help. See no heat in freezing weather.

Helping older relatives stay safe and warm

Older adults are more sensitive to cold and more likely to rely on space heaters. Check that their heaters meet the safety rules, that CO and smoke alarms work, and that their furnace or boiler has had a fall tune-up. A maintenance plan with priority scheduling gives peace of mind during cold snaps.

Myths about space heaters

• "A space heater always saves money." Only if you heat one small room briefly and turn the main heat down. Several heaters running for hours often cost more than a working central system.
• "It is fine on an extension cord if the cord is thick." Manufacturers and fire safety groups say to plug directly into a wall outlet. Power strips and many cords are not rated for a heater's continuous load.
• "Newer heaters are safe to leave on overnight." Safety features reduce risk but do not remove it. Turn them off when you sleep or leave.
• "Closing vents in unused rooms and using a heater elsewhere saves energy." Closing vents can upset airflow and make your system work harder. See closing vents myth.

What to do if a space heater trips a breaker or smells hot

Turn it off and unplug it. A heater that trips breakers, scorches the outlet, smells of hot plastic or makes buzzing sounds should not be used again until the outlet and circuit have been checked. Discoloration or warmth around a wall outlet is a warning sign for an electrician.

Before you plug in this winter

• Test smoke and CO alarms
• Inspect the heater's cord and safety features
• Clear three feet around where it will sit
• Plan to turn it off at night
• Book a heating tune-up so your main system is ready

Fix the cold room for good

We find out why rooms stay cold and fix the cause: airflow, ductwork, radiators, zoning or the heating system itself. We serve every town in Ocean, Monmouth, Burlington and Middlesex counties with same day service and a 24/7 emergency line, including Brick, Toms River, Willingboro and Perth Amboy. Book online or call us.