Why does my iMac fan keep running? (6 Factors)

Cooling fans are inevitable in every electronic product, especially in a computer system. The fans help in removing the heat generated from the hardware components and enable them to work efficiently.

In modern computers like the iMac, you can find the fans to run at a higher speed only when there is an increase in temperature. Other times, they are usually quiet. What if the fans are continuously running in iMac? Let us find out the reasons in this article.

Why does my iMac fan keep running

Why does my iMac fan keep running?

The iMac fans can keep running due to the following factors:

  • Too many processes running in the background
  • Temperature sensor issues
  • Faulty SMC
  • Malware
  • Dust Accumulation
  • High Ambient Temperature

Background Processes

Most of the time, hardware components get very hot due to the continuous running of applications in the background.

Usually, applications are designed to provide a better user experience with snappy performance. So, for the user to access the program instantly, the applications keep running in the background. This will avoid the necessity to boot the application every time the user accesses it.

But this will pressurize the CPU, RAM, and storage to keep running. Imagine a bunch of such applications running in the background. This will make the components use a lot of processing power and heat will be expelled.

To combat the heat, fans have to keep running and when there is a heavy rise in temperature, they might even work at a higher speed.

Temperature Sensor Faults

Every iMac has an inbuilt temperature sensor that will monitor the increase and decrease in internal temperature. Also, it will signal the cooling fans to increase or decrease their speed.

When there is a fault in this sensor, it cannot properly signal the fans and it will lead to the continuous running of the cooling system.

One other drawback of this fault is that you cannot find the faulty sensor on your own and requires a proper diagnostic tool. So, you might have to take the iMac to an Apple store to get it sorted.

Faulty SMC

SMC denotes the System Management Controller which controls the various hardware components in an iMac. This SMC is also responsible for the fans and their control. 

When there is an error with the SMC, it can cause the fans to keep running despite the information from sensors and lower CPU usage.

You can easily resolve this fault by resetting the SMC and it will fix the fans. But when it didn’t fix it, you have to go for other reasons.


Malware is one of the top reasons for the increase in background processes and CPU usage. These sneaky programs can get into the software applications of the iMac and keep them running in the background.

This malware does this to collect information from the computer and can lead to data theft. Your computer will not be safe and can suck too much power to run the processes continuously.

Due to these excessive background applications, the fans will start to kick in and run at a high speed. Until you find the application affected by the malware and clear it off from the iMac, you cannot lower the fans.

Dust Accumulation

Sometimes, if you have placed the iMac in a dust-borne area or you haven’t cleaned your iMac for a while, dust can start to accumulate on it.

The dust can be sucked into the exhaust vent and start to sediment over the fans. Due to heavy dust accumulation, the cooling will not be efficient. 

The dust can also sediment over the hardware components reducing their ability to transfer the heat to the cool air.

Eventually, the dust can block the exhaust vents and cause the iMac to heat up which will force the fans to keep running all the time.

High Ambient Temperature

Although the internal temperature of the PC is monitored by the sensors, you also have to maintain the external ambient temperature.

For example, if you keep the computer in a hot environment, the air being sucked into the device will also be hot and it will not effectively remove the heat expelled by the computer.

So, if you are in a room with elevated temperatures, the iMac will keep on running its cooling system continuously to combat the rising internal temperature.

These are reasons for the iMac fans to keep running and you have to rectify these issues to stop the fan from continuously working.

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Is it safe that the iMac fan is running too much?

No, it is not safe for the iMac to have the fans running continuously. Over time, the fans will become damaged due to excessive running and the cooling system will be collapsed.

Also, if the fans run continuously, they will start to make a loud noise and eventually becomes a nuisance. 

Since the fans will become inefficient after continuous usage, the hardware cannot expel the heat and work efficiently. Thus, it will lead to poor performance.

When the fans run continuously, they will draw more power. So, you have to stop the fan from running continuously and let it decrease and increase as per the internal temperature.

If you find your iMac to have the fans running continuously without any ups and downs, then you must try to fix the issue causing it and rectify it as soon as possible.

Pros and Cons of iMac fans keep running

Pros Cons
Heat will be removed continuously Continuous running of fans will degrade the life of fans.
Performance may increase at times More power will be drawn for cooling.
Loud noise may start to emerge after a few days.
May not be efficient for the iMac performance.


If you are using an iMac and it seems to keep the fans running continuously without any obvious reasons, then you have to find out the underlying condition that causes it. If you find it and solve the issue, you can have a noise-free, quiet environment that will help you to work peacefully. 

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