Using a space heater without starting a fire.

Plug it directly into a wall outlet, never into an extension cord or a power strip. One heater per circuit. Three feet of clear space on every side. Switch it off when you leave the room and when you go to sleep, unless it is a model specifically designed to be left running and it has tip over and overheat protection.

Portable heaters are involved in a large share of home heating fires and in a disproportionate share of the deaths from them, and the causes repeat.

The rules, and why each one exists

Straight into a wall outlet. As above. Also not into a plug adaptor or a multi way plug.

One per circuit. Two heaters on one circuit will trip a breaker if you are lucky and overheat the wiring if you are not. Why a breaker that keeps tripping is telling you something.

Three feet of clearance. From bedding, curtains, upholstery, clothing, paper, and furniture. This is the single most common ignition path: something soft ends up too close, usually because the heater was moved or the bedding shifted.

On a hard, level surface. Not on carpet unless the manufacturer permits it, not on furniture, and not on anything that can tip.

Never in a bathroom unless it is specifically rated for one, and never where it can be splashed.

Not while asleep or out of the room. Most fatal heating fires happen at night.

Never to dry clothes. Not on it, not draped near it, not in front of it.

Out of the path of children and pets, and where the cord will not be tripped over.

Look for a safety certification mark from a recognized testing laboratory, and for tip over shut off and overheat protection. Both are standard on current models and both are absent on the cheapest ones.

Check the cord each time: no fraying, no damage, and not run under a rug or through a doorway.

Which kind to buy

Electric convection or ceramic, with tip over and overheat protection, is the sensible default for a room with people in it.

Oil filled radiators run cooler on the surface and hold heat, which makes them safer around children, at the cost of taking longer to warm a room.

Infrared or radiant heaters heat objects and people rather than air, which is efficient for one person in one place and makes the clearance rule more important, because the element is genuinely hot.

Anything that burns fuel indoors and is not vented outside is not on this list. Kerosene and propane heaters, stoves, and grills are how people are poisoned.

What they cost to run

Electric resistance heaters are all essentially the same efficiency, which means a 1,500 watt heater costs the same to run whatever it is called and whatever the marketing says. There is no electric heater that produces more heat per unit of electricity than another.

What differs is where the heat goes. Heating one occupied room with a portable heater while the rest of the house is cold is often cheaper than heating the whole house. Running four of them is not.

A heat pump is the exception, because it moves heat rather than making it, which is why it is a different category of appliance and not a portable one.

Smoke alarms, while you are here

If a portable heater is running in the house, the smoke alarms matter more than usual. Test them, and replace any that is more than about ten years old.

Fit carbon monoxide alarms too, on every level. They are irrelevant to an electric heater and essential to every other kind of improvised heat, and the cold snap that has you reading this is exactly when someone reaches for a stove.

The short version

Wall outlet only, one per circuit, three feet of clearance, hard surface, off when you leave or sleep. Warm plug means stop. Buy one with tip over and overheat protection. All electric heaters cost the same to run per unit of heat, so ignore any claim otherwise.