Why Does My Space Heater Keep Turning Off and On?

When a space heater keeps turning off and on, it can be a frustrating and potentially dangerous issue. The root cause of this problem often lies in the technical specifications and power requirements of the space heater, as well as the electrical system it is connected to. In this comprehensive guide, we’ll dive deep into the technical details and provide a step-by-step DIY troubleshooting process to help you resolve this issue.

Technical Specification

Power Requirements

The power requirements of a space heater are typically measured in watts. For example, a 1500-watt space heater will require a power supply that can provide at least 1500 watts of electricity. If the power supply is insufficient, it may not provide the required electricity to power the space heater, resulting in it turning off unexpectedly.

Electrical Current

The electrical current required to power a space heater is measured in amps. For example, a 1500-watt space heater that operates on a 120-volt electrical system will require approximately 12.5 amps of electrical current (1500 watts / 120 volts = 12.5 amps). If the electrical current is insufficient, it may not provide the required electricity to power the space heater, resulting in it turning off unexpectedly.

Circuit Breaker

The circuit breaker that protects the electrical circuit from overcurrent is typically rated for a specific amperage. For example, a 15-amp circuit breaker is designed to protect circuits that require up to 15 amps of electrical current. If the electrical current exceeds the rating of the circuit breaker, it will trip and shut off the electrical circuit to prevent overheating and potential fire hazards.

DIY Troubleshooting

why does my space heater keep turning off and on

Step 1: Check the Power Level

Start by trying the space heater on a lower power level. If the heater is on the highest setting, it may be drawing too much current and causing the circuit breaker to trip. Reducing the power level can help alleviate this issue.

Step 2: Unplug Other Appliances

If the space heater is on a circuit with other appliances, try unplugging those appliances to see if the issue persists. If the heater stops turning off and on after unplugging other devices, it’s likely that the circuit was overloaded, causing the breaker to trip.

Step 3: Move the Heater to a Different Outlet

Try moving the space heater to a different electrical outlet, preferably one on a different circuit. This can help determine if the issue is with the specific outlet or the circuit itself.

Step 4: Check the Air Filters

Dirty or clogged air filters can restrict airflow, causing the space heater to overheat and turn off. Regularly clean the air filters to ensure proper airflow.

Step 5: Adjust the Thermostat

If the thermostat is set too low, the space heater may turn off after reaching the desired temperature. Conversely, if the thermostat is set too high, the heater may keep turning on and off to maintain the set temperature. Adjust the thermostat to the desired temperature and monitor the heater’s behavior.

Step 6: Inspect the Electrical Connection

Ensure that the space heater’s power cord is securely plugged into a properly functioning power outlet. Check for any signs of damage or wear on the cord or plug.

Step 7: Check the Circuit Breaker

If the space heater continues to trip the circuit breaker, check the breaker to ensure that it is rated for the required amperage. If the breaker is old or weak, it may need to be replaced.

If you’ve followed these troubleshooting steps and the issue persists, it’s best to contact a professional electrician who can further investigate the problem and provide a solution.


  1. When the Space Heater Trips the Circuit Breaker – Frye Electric, Inc. (2017-11-02)
  2. Space Heater Keeps Turning Off – Reasons and Quick Solutions (2023-12-14)
  3. When my space heater is on, it keeps turning off the power – Reddit (2023-10-15)