Electricians see the aftermath of space heater accidents more than any other appliance. The physics is simple: a space heater is a 1,500-watt toaster running for hours, and everything about how people actually use them — overnight, on old circuits, through extension cords, near bedding — fights against that physics.
Why overnight is the risk peak
Fire statistics consistently put space heaters at the centre of home heating fires, and the deaths cluster overnight for an obvious reason: nobody is awake to notice the tipped unit, the curtain that drifted close, or the warm extension cord. Modern heaters have tip-over switches and overheat protection, and those features genuinely help — but they protect against the heater's own failures, not against the receptacle behind the bed slowly cooking, which is where the electrician's half of this problem lives.
A 1,500W heater pulls 12.5 amps continuously. Older bedroom circuits — especially in homes with aluminum wiring or back-stabbed outlets from the 70s and 80s — were never built for that as an all-night, every-night load. The receptacle's connections heat, loosen, and arc over weeks, invisibly, behind furniture. Warm cover plates, a buzzing outlet, or a melted-plastic smell are late-stage warnings: stop using the outlet and have it inspected.
The rules if you're using one anyway
Plug directly into the wall — never an extension cord or power bar. Keep a metre clear of bedding, curtains, and furniture on all sides. Put it on a hard floor, not carpet. Use a model with tip-over and overheat shutoffs. Run it to warm the room while you're awake, then off when you sleep — a heavier duvet beats an unattended heater. And confirm your smoke alarms actually work, because they're the system that turns a fire into a story instead of a tragedy.
The permanent fix costs less than people expect
If a bedroom or office needs heat every night, make it permanent: a hardwired 240V baseboard or wall heater on its own circuit with a real thermostat runs $600–$1,200 installed — safe to run unattended by design, no cords, no portable appliance. Where the heater is solving a draft rather than a heating gap, the energy audit often finds insulation fixes that beat heating the outdoors. Either way, a dedicated circuit visit is a small job for us; call 416-837-4038 before the cold snap, not during it.