My Electric Heater Turns On and Off Repeatedly [Fixed]

One of the common issues people face with electric heaters is that they turn on and off repeatedly. This can be very problematic especially when it is cold outside. 

This repeated on-and-off cycle is called short cycling. It occurs when a heater shuts off before completing an entire cycle. It is an inconvenience during peak winters, and a malfunctioning heating unit can also be hazardous. 

Read on below to find out the main reasons for your electric heater to short cycle and what you can do about it.

Portable heater, womand and cat in living room

How Often Should an Electric Heater Be On and Off? 

If your electric heater turns on and off repeatedly, it might be because it is supposed to do that. An electric heater the correct size according to your home will turn on and off anywhere from three to eight times per hour

If you notice that the turn-on and offs are more than eight times an hour, several factors can influence this. 

  • Outdoor Temperature.
  • Insulation of your home.
  • The build of your house.
  • How old is the electric heater

All these factors will increase the number of cycles per hour, and your electric heater will turn on and off frequently.

Reasons Why Your Heater Is Turning On and Off and How to Fix

Thermostat Issues

A thermostat is responsible for controlling the entire heating system. If there is an issue with the thermostat or if it is placed at the wrong location, it will cause your heating system to malfunction. 

Faulty Thermostat 

A faulty thermostat won’t be able to read the correct temperature. It will then continue to send wrong signals to the electric heater, which will cause the heater to turn on and off repeatedly.

A fault as simple as not having the correct settings can also cause your electric heater to malfunction. Make sure to keep your thermostat always on and set to heating mode.

If your thermostat is programmable, programming overrides may also be causing issues with your electric heater. You should take it to a qualified technician to fix the programming.

Some thermostats function on batteries. When the battery gets low, it can result in your thermostat repeatedly turning off or getting the wrong temperature readings. Replacing the batteries of the thermostat will help resolve this issue.

Wrong Placement of Thermostat

A thermostat will have trouble reading the correct temperature if it is installed in a place that is hotter than the rest of the room. It will result in the thermostat sending incorrect signals to your electric heater.

For example, if the thermostat in your home gets direct sunlight, it will warm up and detect a higher temperature than it is. Similarly, if a thermostat is near an oven or stove which produces heat, it will heat the thermostat and result in the same issue.

To resolve this issue, move the thermostat to an appropriate location.

Clogged Air Filters

A clogged air filter is one of the main reasons for a short cycling heater. When using a forced-air heating system, a clogged air filter can cause your heater to malfunction. 

Electric heaters have a safety feature that shuts them off in case of internal overheating. Clogged air filters result in less cold air flowing inside the heater. 

Insufficient cold air will cause the electric heater to overheat, and the auto shut-off mechanism will activate. It will result in your electric heater to a short cycle and shutting on and off repeatedly. 

When you call a technician for routine maintenance of your electric heating system, they will change the air filter. But you must ensure you clean and change the air filter regularly to avoid overheating the system.

Sequencers Error 

A home electric heater contains multiple heating elements that produce heat through the inside coils. However, not all the heating elements turn on at once, overloading the circuit. It will either blow a fuse or trigger the circuit breaker. 

Every electric heater with multiple heating elements contains a sequencer. It is responsible for switching and spacing the heating elements on and off. A sequencer sets a specific pattern in which all the heating elements will turn on and off. 

A faulty sequencer can result in many heating elements turning on simultaneously, which will trigger the circuit breaker. It can also cause all the heating elements to turn off at once. 

You would need help from a specialist in the electric heating system to determine whether or not a faulty sequencer is a reason. 

Faulty Heat Limit Sensors 

When the internal temperature in an electric heater starts to rise above the specified limits, the heat limit sensor will auto-shutoff the heater t avoid any damage.

In some electric heaters, there are dual heat limit sensors. One is present at the air inlet and another at the air outlet. If any of them detects a higher-than-normal temperature, both shut off the power supply to the heating element. 

A faulty heat limit sensor will sense the temperature as high even when the temperature is within limits. It will result in your electric heater turning on and off repeatedly.

It is highly hazardous, as a malfunctioning heat sensor may not sense overheating and keeps the heater running. It can cause damage to your whole heating system.

It is crucial to get the heat sensor replaced as soon as possible.

Overloaded Electrical Component

An electric heater is made of several components. Some faults can result in any of the electric components of your heater overload. In case of an overload, the circuit breaker will get triggered and cut off the power to the heater.

If resetting the circuit breakers solves the issue for some time, then an overloaded electrical component is the problem. You would need to get professional help from an electrician. 

They will find the overloaded component and replace or repair it to resolve the short cycling of your electric heater.

Also read: How Many Watts Does a Space Heater Use?

Outside Faults

You have checked everything on the list and still have not determined the cause of your electric heater turning on and off. Chances are, the fault is not within your heating system but on the outside of it.

Electric Circuit Fault

The electric circuit in your home can be faulty. Plugging too many devices into the home’s electric circuit can overload. 

The electric circuit in your home is designed to provide a fixed amount of power. If you plug several devices into your electric circuit at once, it will cause overloading. 

If the electric circuit works fine, an overload will result in a blown-up fuse. But if there is an issue with the fuse or the electric circuit itself, overloading will result in low voltage, which in turn will cause the failure of electrical devices. It may also turn your electric heater on and off due to fluctuating voltage.

Check whether or not an overloaded electric circuit is causing your electric heater to malfunction. Turn off some electric devices like your TV, fridge, and other appliances. Then switch on your electric heater.

If it still malfunctions, it is not due to an overloaded electrical circuit. If your heater starts working properly, you need to call a professional electrician to check the electric circuit. 

Weak Power Supply

Unlike the above scenario, when the power supply was sufficient, you plugged in too many devices at once. 

In this case, even though you are not using multiple electric devices simultaneously, your electric circuit is not offering the power needed for your electric heater to run properly. 

To resolve this issue, you would need to call a professional electrician. They will check the output power at the outlet and determine the possible reasons for the weak power supply.

Faulty Power Cord

The cable connecting your electric heater to the power source is quite heavy and can easily take a high power load. But with continuous use over fluctuating, it can get damaged. 

Depending upon the damage’s severity, it may intermittently supply electric power to the heater, which results in repeatedly turning on and off the electric heater.

Improper Size

It is probably the worst possible reason. If your electric heating system is too large compared to your home size, it will warm your space quickly. Now that does not sound like a problem. But, an electric heater too big will result in interrupted heating. 

The temperature will rise too fast, resulting in your electric heater turning on and off frequently to maintain the temperature. Not only does it take a toll on your heating system, but the electricity bill skyrockets.  

If the electric heater is too big, you may need to reinvest in a new electric heater that is the right size per your needs. In such scenarios, you may consider using a space heater for your home.

And if you want to try another type of heater, check out my selection of the 6 Best Non-Electric Space Heaters.

Wrapping Up

A faulty electric heater can leave you frustrated during winter. To resolve this issue, it is essential to get to the root cause of the problem. When dealing with a faulty heating system, it is better to call a professional for help to avoid any mishaps.

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