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Why a space heater trips the breaker

Updated September 19, 2026

A 1,500 watt heater draws 12.5 amps on its own. That is 1,500 watts divided by 120 volts, and it is the number on the listings. As general guidance, many household circuits are 15 or 20 amps and feed several outlets. Put a heater on a circuit that is already running a computer, a TV or a vacuum and the total can pass what the breaker allows. The breaker trips. It is doing its job.

Warning signs that are more than a nuisance

ESFI lists these signs of an overloaded circuit: flickering, blinking or dimming lights, breakers that trip or fuses that blow often, warm or discolored wall plates, cracking, sizzling or buzzing from outlets, a burning smell from outlets or switches, and a mild shock or tingle from appliances or switches. If you see any of the heat, smell or sound signs, unplug the heater and call a licensed electrician. Do not keep resetting the breaker.

What to do

• Give the heater its own outlet. ESFI says to plug only one heat-producing appliance into an outlet at a time, and not to plug any other device into the same outlet as a space heater.
• Move other loads off the circuit. Outlets in one room, and sometimes the next room, often share a breaker. Your panel label may tell you which.
• Use a lower setting. The Amazon Basics Ceramic 1500W lists 900 watts on low, which is 7.5 amps. The De'Longhi EW7707CM has three power levels.
• For a desk, drop to 200 watts. The Lasko MyHeat 101 draws about 2 amps. Lasko's listing says the low draw is the point: it will not keep tripping an office breaker.
• Never run two full-size heaters on one circuit. Two of them draw 25 amps.

What never to do

• No extension cords or power strips. The CPSC and ESFI both say to plug an electric heater directly into a wall outlet. ESFI notes that a power strip only adds outlets. It does not add power, and it can overheat.
• Do not swap in a bigger breaker. The breaker is sized to protect the wire in the wall. That is a job for a licensed electrician, who may run a new circuit.
• Do not ignore a warm plug. A plug or wall plate that gets warm points to a worn outlet or loose connection. Stop using that outlet until an electrician has looked at it.

Power draw of the picks

This page is general guidance, not electrical advice. Homes differ, and older wiring deserves extra care. When in doubt, ask a licensed electrician.

Check your own room with the size and power use calculator, or compare all seven picks on the roundup page.