Intech Blog

Space Heater Safety: What Twin Cities Homeowners Should Know

Published September 23, 2026 · Intech Corporation · Twin Cities, MN

No, you shouldn't plug a space heater into an extension cord or a power strip, and you shouldn't run one on the same circuit as anything else that draws real power. A typical 1,500-watt space heater pulls around 12.5 amps, which is most of what a standard 15-amp household circuit is rated to carry. If that outlet feels warm, the breaker keeps tripping, or the cord gets hot to the touch, your electrical system is telling you something real, not just having a bad day.

The National Weather Service puts the normal first freeze for the Twin Cities somewhere between October 1st and 10th, which means space heaters are already coming out of closets and garages across Minneapolis and St. Paul. That's also right around when Fire Prevention Week runs every year, and heating equipment stays one of the more stubborn causes of home fires once the weather turns.

Here's the part that surprises people: space heaters and heating stoves account for nearly a third of home heating equipment fires, but they're responsible for over seven out of ten of the deaths and seven out of ten of the injuries tied to those fires, according to NFPA data coveringthrough 2024. That's a wildly lopsided ratio, and it's not because space heaters are exotic or rare. It's because people plug them into whatever outlet is closest, run them on extension cords, and leave them running in rooms nobody's watching.

Why a Space Heater Overloads a Circuit So Easily

Most portable electric heaters draw close to the maximum a standard 15-amp circuit is designed to handle, especially once you factor in that code doesn't want a continuous load eating up the full rated capacity of a circuit for hours at a time. Add a lamp, a phone charger, or a TV on the same circuit and you've got a recipe for a breaker that trips every time the heater cycles on.

That's not a defect. That breaker is doing exactly what it's supposed to do. The problem is the load, not the breaker.

Never Run One on an Extension Cord or Power Strip

Every major safety organization says the same thing here, and it's not a suggestion. Space heaters should be plugged directly into a wall outlet, never into an extension cord or power strip. Extension cords and power strips are built for light, intermittent loads, not for a device pullingamps continuously for hours. The internal contacts and thinner wiring inside a cheap cord heat up faster than most people realize, and that heat builds quietly until something melts, arcs, or ignites.

If the only outlet in the room is across the space, that's a sign you need a proper receptacle installed closer to where the heater actually needs to sit, not a workaround with a cord.

What a Tripping Breaker Is Actually Telling You

A breaker that trips a few minutes after you turn the heater on is almost always a simple overload. Try the heater on a different circuit in another room, one with nothing else plugged in. If it runs fine there, your original circuit just doesn't have the spare capacity, and that's worth having checked rather than fighting with the breaker every night.

A breaker that trips instantly, or pops with a loud snap the moment you plug something in, is a different animal entirely. That points toward a short circuit somewhere in the heater, the outlet, or the wiring behind it, and it's not something to keep resetting and hoping goes away. If the plug, cord, or outlet ever feels hot to the touch, unplug the heater and stop using that outlet until an electrician takes a look. That's one of the few genuinely safe DIY checks here: unplug it, note which outlet, and call someone before you plug anything back in.

Older Homes and Older Panels Add Risk

A lot of homes across the Twin Cities were wired decades before space heaters, EV chargers, and induction ranges were part of anyone's electrical plan. Homes with aluminum wiring or an old Federal Pacific or Zinsco panel don't always trip the way they're supposed to under a sustained load, which means the breaker isn't always the safety net you think it is. If your panel is decades old and you're leaning on space heaters every winter, that's worth a conversation, not a guess.

The longer-term fix for a house that consistently needs supplemental heat in certain rooms usually isn't a bigger heater. It's enough spare capacity in the panel and, in some cases, a dedicated circuit run to the room that struggles most. That's a real project, but it solves the problem instead of managing around it every October.

Offices, Shops, and Warehouses Have the Same Problem

This isn't only a residential issue. Employees tuck space heaters under desks in offices all winter, and that combination of a hot appliance, a confined space, and nearby paper or plastic waste bins is exactly the setup fire codes try to prevent. Commercial spaces also tend to have more devices sharing circuits than most people realize, especially in older tenant spaces that have been remodeled and re-carved over the years without anyone rebalancing the electrical load.

If your building has cold corners that staff keep fixing with personal heaters, that's usually a sign of a heating or electrical capacity gap worth solving properly. Our tenant improvements and preventative maintenance work regularly turns up exactly this kind of issue during routine walkthroughs, before it becomes a bigger problem.

A Few More Habits Worth Keeping

Beyond the outlet and circuit questions, a handful of basic habits cut most of the remaining risk down to almost nothing.

• Keep anything that can burn at least three feet away from the heater on every side.
• Never leave a space heater running when you leave the room or go to sleep.
• Set it on a flat, hard, level surface, never on carpet, furniture, or a rug.
• Check the cord and plug periodically for warmth, fraying, or discoloration.
• Buy a model with a tip-over switch and automatic overheat shutoff; older heaters often lack both.