Window air conditioner keeps running when turned off? Top 4 reasons why

There is nothing more frustrating than a window air conditioner that won’t turn off. You keep thinking about the high electricity bill that is continuously accumulating every extra minute. If you are in such a situation, then you have come to the right place. Below are the top 4 reasons why your window air conditioner keeps running when turned off.

1. Electronic Control board problems

If you have a modern window air conditioner, then the chances are that it features a PCB – also known as an Electronic Control Board. Now, your window air conditioner has individual components that need a central control center. The PCB acts as the controlling module for your entire air conditioner.

When your window AC keeps running after the set temperature is attained, then the output relay might have a glitch. You have to replace the entire Electronic Board if you want to fix the relay problems. However, if the relay board is not included in your Electronic board, then the sensors might be damaged. Use a multimeter to determine where the problem lies before making any replacements.

2. Temperature Sensor Problems

The temperature sensor is a crucial component of all window air conditioners. Its primary purpose is measuring the room temperature and relaying the information back to the compressor. What this implies is that the compressor will keep running until the right temperature is attained.

However, what happens when the temperature sensor malfunctions? In such a situation, then the compressor will keep running because they are no signal to stop it. Start by checking whether the temperature sensor is connected correctly to the control board.

3. Thermostat problems

In some situations, the temperature sensor might send the required signal to the compressor. However, a faulty thermostat might hinder the compressor from stopping. The thermostat supplies the compressor with the power that it needs to function.

A faulty thermostat will keep in supplying power even when signaled to stop. When you establish that the Electronic Control board and temperature sensor are working correctly, then the likely cause of the problem is a faulty thermostat. Get a qualified AC contractor to help you with the thermostat repairs. You don’t want to end up having a window air conditioner that requires constant fixing.

4. Undersized window air conditioner

In some homes, the window air conditioner is classified as undersized. What this means is that the air conditioner doesn’t have the required capability to service the expected space. The system will struggle to keep up with the temperature changes, which means that it will keep running.

In such situations, the best solution is getting a bigger window air conditioner. Yes, we understand that they can be quite expensive. However, a bigger air conditioner is always worth every dime that you spend.


You need a certified air conditioner contractor to carry out regular checkups and maintenance on your appliance. Fixing the highlighted issues is somewhat complicated, and you will need professional assistance. Periodic maintenance also saves you substantial repair amounts in the long run.

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