A dirty CPU heat sink

Is dirt and dust damaging your desktop?

Last Updated on September 6, 2020 by Christopher G Mendla

Even the cleanest homes and offices are a source of dirt and dust which can build up and end up damaging your desktop

Dust and dirt will damage your desktop

When the CPU in your desktop is working, it generates heat. The harder it works, the more heat is generated. 

Heat will cause the components in a computer to fail. There are a number of factors involved but generally the hotter the machine runs, the more likely that a component will fail. Also, the more variation in temperature, the more likely a component will fail. 

If your desktop is ‘not doing anything’, there is a minimal load on the processor and therefore minimal heat. However, when you start working with the machine, the load on the processor increases which causes increased heat. 

The heat is centered in the CPU or Central Processing Unit. This is a distinct chip or chips usually on the motherboard of your machine. 

In order to control and dissipate the heat, most desktop computers will use a heat sink and a fan. 

The heat sink

The heat sink is a piece of aluminum with fins that attaches directly to the CPU. Heat simply radiates from the CPU, through the fins and into the air. This is similar in function to a car or house radiator. This is a passive system and is limited in it’s capacity for controlling heat. 

The fan

In order to make the heat sink more efficient, a fan is employed in the design. The computer will sense the temperature of the CPU and increase the speed of the fan as necessary. This helps to keep the CPU at a more constant temperature. 

In addition to the CPU fan, there is usually a fan that pulls air through the desktop enclosure.

The problem with pulling air through the desktop case is that you are also pulling dirt and lint that is in the air. The concentration of dirt and lint might be minuscule but, over time, it becomes significant. The problem is that, in many cases, the electrical charge of the components acts somewhat as an electrostatic air filter. In other words, the design of the machine attracts dust and dirt to the heat sink.

An example:

The picture below is of a typical motherboard. The circular object is the fan and heat sink over the CPU. It measures about 2 1/2 to 3″ . The images above are from a machine that was in a very clean home for 7 years. In some cases, significant dust can accumulate in as little as a year.

The image below is of the heat sink with the fan removed. You can clearly see the build up of dirt and  dust. This will greatly reduce the efficiency of the heat sink. 

The other component that is very susceptible to dirt is the power supply. A typical power supply uses a fan or fans to dissipate the heat generated. Incoming air typically comes through a grill of small holes. These holes can get a ‘blanket’ of lint which will eventually cause the power supply to overheat. 

Cleaning your desktop

There are two ways of cleaning the machine. First is to vacuum all any lint that is visible on the case such as the power supply above. The second is to open the case and use compressed air to blow the dust out.

Vacuuming the exterior

Vacuuming is simple. Every month or so, run the brush attachment from your vacuum over any grills where dust is accumulating. 

Cleaning the interior

Cleaning the inside is a bit more complicated. 

When you clean the inside you run a risk of damaging the machine and/or losing data. Use care and be sure to have a backup of your data.

You should have the machine off and unplugged. Look for the CPU and heat sink. Use compressed air to gently blow the dust from the heat sink. If you use a compressor BE SURE TO LIMIT THE PRESSURE TO NO MORE THAN 10 PSI, 15 PSI max. USING A HIGHER PRESSURE CAN DAMAGE CIRCUIT BOARDS. 

Also, you will be blowing a lot of ancient dust around. Wearing a mask and eye protection might be a good idea. This procedure probably only needs to be done once a year. 


There are a few steps you can take to minimize the impact of dust and the related heat:

  • Vacuum the room where the desktop sits regularly
  • Make sure that the filters for your HVAC systems are properly maintained. 
  • Consider a portable HEPA filter for the room. 
  • Pets may increase the amount of dust and dirt. 

CASE STUDY – I was the Director of Information Systems for a University. The Lucent telephone switch was experiencing failures about once a month. The switch was crammed into a tiny operator’s office. Dust would build up on the circuit boards causing failures.

I placed two HEPA filters in the room and had the filters cleaned regularly. The failures only happened every four to six months after the filters were installed.


Laptops are also susceptible to heat damage. However, they usually don’t accumulate dirt on the exterior. Disassembling a laptop requires skill and, in many cases, some special tools.

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