Miami gets a handful of cold mornings a year, and when one arrives, space heaters come out of closets all over town and breakers start tripping. The rest of the year, the same circuits carry dehumidifiers in closets and garages, and portable air conditioners in rooms the central system does not reach. All three are heavy plug-in loads, and all three are among the most common reasons a bedroom or living room breaker trips.
Why a space heater trips a breaker
A typical space heater on its high setting uses about 1,500 watts. At 120 volts that is about 12.5 amps, most of what a 15-amp circuit can carry, from one appliance. Bedroom and living room circuits usually also feed other outlets and often the lights. Add a second heater, a hair dryer or a vacuum on the same circuit and the breaker trips. That kind of trip usually comes after a delay of seconds to minutes, because the breaker is responding to heat building up in the wire.
A trip the instant the heater is switched on is different. It points to a short in the heater or its cord, and that heater should not be used again until it is checked or replaced. On bedroom circuits with arc fault breakers, a damaged heater cord or a loose plug can also trip the AFCI; see breakers that trip at night.
What CPSC and NFPA advise
The Consumer Product Safety Commission's 2026 winter safety release tells consumers to keep portable heaters at least three feet from drapes, furniture, bedding and other combustible materials, to plug electric space heaters directly into a wall outlet and never into an extension cord or power strip, and to turn heaters off when sleeping. It links portable heaters to roughly 1,600 fires a year, with an average of 70 deaths and 150 injuries a year from 2020 to 2022.
The NFPA's electric space heater safety tip sheet adds two points that bear directly on tripping breakers: do not plug anything else into the same wall outlet as the heater, and check often that the plug fits snugly. If it is loose or the plug gets very hot, the outlet needs to be replaced by an electrician.
Why a power strip is the wrong fix
When a heater trips a breaker, the tempting move is to plug it into a power strip or extension cord running to another room. Most power strips and household cords are not built for that current, and their contacts and thin wires heat up. The breaker in the panel protects the wall wiring, not a cord on the floor. If the heater keeps tripping a circuit, the answer is to take other loads off that circuit, not to add a strip.
Dehumidifiers
In Miami, dehumidifiers run for months in closets, garages and converted rooms. They contain a compressor and a fan, and they cycle on and off by themselves, which is why they show up in overnight trips. A full bucket or a clogged filter makes them run longer. Recalls are worth checking: the CPSC announced a 2023 recall of about 1.56 million Gree dehumidifiers for fire and burn hazards, sold under brands including Kenmore, GE and SoleusAir, and lists other dehumidifier recalls on its dehumidifier recalls page. If yours is on a list, stop using it.
Portable air conditioners
A portable or window AC unit in a bedroom, an addition or a converted garage draws a heavy, steady current, and its compressor pulls more each time it starts. Check the amps on its label and the instructions for the outlet it needs. A large unit sharing a circuit with a computer, a TV and the lights is a common reason a room's breaker trips on hot afternoons. Warm plugs and outlets are an early warning; see outlets warm to the touch.
How to use them without tripping breakers
- One heavy appliance per circuit. Turn breakers off one at a time to find which outlets share a circuit, and spread heaters, dehumidifiers and portable AC units across different ones.
- Straight into the wall. No power strips, no extension cords, nothing else in the same outlet.
- Use the low setting on a heater in a small room; it may be all you need.
- Replace worn outlets that do not grip the plug firmly.
- Reset once. If a breaker trips again with the heater unplugged, the problem is not the heater. See breakers that trip again on reset.
- Stop using any unit with a hot, discolored or damaged cord or plug.
When it needs more than moving a plug
If a room needs a portable AC or dehumidifier every day, a circuit of its own may be the right answer; see when an appliance needs its own circuit and dedicated circuits. If outlets are scorched, a breaker feels warm, or you smell burning, stop using the circuit and see burning smells and buzzing.
What we check
We map which outlets are on which circuit, measure the load with the appliance running, check the outlet and its connections for heat damage, and test the breaker. Then we tell you whether moving loads is enough, or whether a circuit needs repair or a new circuit is worth adding. Our guide is it the appliance or the circuit? covers the process.
Questions people ask
Is a heavy-duty extension cord OK for a space heater?
The CPSC's current advice is to plug space heaters directly into a wall outlet and never into an extension cord or power strip. Follow that and the heater's own instructions.
Can I replace the breaker with a bigger one?
No. The breaker is sized to protect the wire in the wall. A bigger breaker lets that wire overheat instead of shutting off.
Why does the heater trip the breaker but the dehumidifier does not?
A heater draws its full current the whole time it is heating. Most dehumidifiers draw less. Together on one circuit, they can add up.
Need it looked at?
KRW Electric (EC13012832) troubleshoots and repairs circuits that trip when a heater or portable AC is plugged in in Pinecrest, Coconut Grove, South Miami and Miami Beach, with same-day service when scheduling permits. Call (305) 359-7312 and tell us what you are seeing. We will ask a few questions, tell you whether it sounds urgent, and give you the earliest time we have. Our before you call checklist covers what to have ready, and what happens on a repair visit explains the rest.
Reviewed by Kyle White, KRW Electric Company LLC — licensed electrical contractor EC13012832.
