PC Airflow Guide: A Guide for Configuration of PC Fans

Using PC case fans to ensure your computer is adequately cooled isn’t rocket science, but it may be difficult. Sure, you could go for “maximum power” by cramming as many fans into and onto the casing as possible, but that’s far from ideal.

The setup must have a rhyme or rationale to it, otherwise, it will become completely inefficient. We explain the foundations of computer air cooling so you can prevent a catastrophe like Chornobyl.

Ventilation and case fans

Every fan has cubic feet per minute (CFM) rating that indicates how much air it moves each minute. A fan’s CFM indicates how much air it moves.

You’ll need enough case fans to push and draw air into and out of the case to adequately air cool your computer. Greater case fans equal more overall CFM and air movement through your computer.

Just be aware of the noise levels, since fans may make a lot of noise. Use fewer or quieter fans to keep your computer from becoming overly noisy. Furthermore, the major feature of your case fans should not be flashing multicolor lights.

Use adequate fan placement

Air passes through a fan in one direction and out the other. A fan may be used as an intake or exhaust by shifting the direction in which it is positioned. You should also pay attention to where the fans are placed.

The air should flow freely through the casing. The case fans in front of the case should pull in the air while the fans at the back should blow it out.

Because hot air rises, any vents on the top of your case should be used as exhaust fans. Intake should be done using side-mounted fans, which typically do not have air filters. You may custom manufacture your own filters to avoid dust difficulties.

The quiet killer is dust

When it comes to dust, you’ll want to keep your computer as dust-free as possible. Otherwise, all the ventilation in the world won’t be able to keep your components cool. Make sure that the air entering the case first goes through a filter to minimize dust. Many cases feature filters that may be removed and cleaned with a short rinse. Just be sure to clean the filters every now and again. You diminish airflow and cooling power by leaving filters unclean or dusty.

Air pressure (positive vs. negative)

One of the most hotly argued subjects in computer cooling is the optimum air pressure for a computer case. A computer case may have one of two features:

  • Positive pressure – Because the case fans push more air into the case than they draw out, the air pressure within the case is higher.
  • The air pressure within the case is equivalent to the air pressure outside the case. If you leave the case open, it will be difficult to get.
  • Negative pressure occurs when more air is drawn out of the case than is forced in, resulting in a vacuum.

To calculate pressure, add the CFM of all the intake and exhaust fans together. Positive pressure exists when the intake CFM is larger than the output CFM.

Negative pressure occurs when the exhaust CFM is larger than the intake CFM. When the intake and exhaust CFM are equal, you have reached neutral.

You’d have neutral pressure with an enclosed enclosure in an ideal world since no dust would be dragged in. Negative pressure implies air is being pulled into your case via all of the small openings you can’t control and aren’t filtering, resulting in less effective cooling over time.

Aim for slightly positive pressure, with intake CFM slightly greater than exhaust CFM. As a result, the air entering your case passes through a filter first.

Final Thoughts

When creating your computer, keep the ideas stated above in mind when configuring your cooling system. Otherwise, you can wind up with a computer that looks like a toaster oven. Just stay away from the office’s gaudy LED-equipped case fans.

Aside from fans and vents, the various tiny spaces in the chassis and surrounding sections are also key entry opportunities. Unless you wish to place caulking or sealer in your case, you can’t truly restrict airflow at these spots.

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