PC Case Airflow Pressure &
Dust Prevention Calculator
Calculate net CFM flow differential, balance intake and exhaust fan curves, and prevent your gaming rig from turning into a dusty vacuum.
โ๏ธ Intake & Exhaust Fan Layout
๐จ Airflow Engineer Assessment
Your PC operates in ideal slight positive pressure (+68.0 CFM). Clean air enters exclusively through your dust-filtered front panel, while the positive internal pressure pushes dust outward through unfiltered chassis holes and PCIe brackets.
Frequently Asked Questions
Why is Positive Air Pressure better than Negative Pressure for gaming PCs?
Positive pressure occurs when total intake airflow (CFM) is greater than exhaust airflow. The excess filtered air continuously pushes outward through unfiltered case seams, PCIe bracket holes, and port gaps. Negative pressure turns your PC into a vacuum cleaner, sucking unfiltered ambient dust and pet hair through every crack and crevices.
How much does a liquid cooling radiator restrict fan airflow?
A standard liquid cooling radiator with 18 to 22 FPI (fins per inch) creates heavy static pressure resistance, reducing effective fan airflow by approximately 25% to 35%. Three 120mm fans mounted on an AIO radiator push significantly less air than three unobstructed intake fans.
What is the ideal ratio of intake fans to exhaust fans?
The golden rule is having slightly more intake CFM than exhaust CFM (e.g. 3 intake fans running at 1100 RPM and 1 rear exhaust fan running at 900 RPM). This ensures smooth positive pressure without creating internal heat pockets.