Should my computer fans be sucking or blowing?
Question
Should my computer fans be sucking or blowing?
Answer
Heatsink and CPU fan
A heatsink on the processor or other chip on the motherboard, video card, or other circuit board in the computer can suck or blow depending on the make of the heatsink and configuration of the computer. A heatsink that is both active and passive will often blow air through the finned radiator to help allow for the heat to escape.
Case fans
Your chassis configuration will determine whether or not the fans should be blowing or sucking. Computer cases that have only one fan in the back should always be blowing the hot air out. Another common configuration is to have the fan in the back with a fan in the front portion of the case sucking in air in.
As can be seen in the picture to the right, the computer case brings in cold air from the front of the case. Because it's always open and not constrained, and as the lighter hot air rises in the case, it is blown out the back. The important thing to remember is, when working with a computer that has more than one case fan, at least one should be sucking air in and one should be blowing air out. Having all fans blowing in with cool air would give the hot air no way to escape.
Tip: It may not be necessary to have a case fan in the back of the computer if the computer has a power supply with an intake fan that blows hot air out the back.
Other related questions
Should fans mounted on the top of the case suck air in or blow air out?
As mentioned above since hot air rises we suggest that if you're building a case that has additional fans added on the top that those fans be blowing hot air out of the case.
How should side case fans be mounted?
If you're building a case and creating fans on the side of the case, we suggest that they be blowing air into the computer.
Additional information
- How can I tell if my computer case fan is sucking or blowing air?
- What temperature should my processor be running at?
- See the computer case fan definition for additional information and related links.