To achieve optimal airflow and less dust accumulation, it’s recommended to opt forneutral pressureorslightly leaning towards positive.
With more intake than exhaust fans (orjust balanced), dust won’t enter the case from every nook and cranny. Instead,hot air tries to escapefrom every gap, and theconstant air supplykeeps the components cool.
That doesn’t mean negative pressure is that terrible. Such a configuration isideal for users who have dust-free surroundings and whose components overheat excessively.
Let’s get deeper and discuss why a slightly positive pressure is better.
Why I Recommend Slightly Positive Pressure
For beginners, positive pressure is wheremore air comes in than goes outof the PC case. you may achieve this by installingmore intake fans than exhaust.
But we don’t want all or too much intake as it leads to difficulty in hot air dissipation. ensure youinstall an extra intake fanwhenever you go for one exhaust.
In an ideal setup, this means2 to 3 intakeand1 to 2 exhaust fans. This way, you’ll have a balanced airflow and air pressure slightly leaning toward positive.
In a setup with a balanced number of fans, running theintakes at a higher speedthan the exhausts should also do.
This configuration has the following benefits:
Maintains Proper Airflow
When thenumber of fansis balanced out, thesame amount of airthat’sbrought in from the front or bottomisexhausted from the rear or top.
It does look like that’s the best approach to go for. However, in real-life scenarios, thecomponents’ temperaturesrise unexpectedly and require extra effort to throw out hot air.
Aslightly negative air pressure(with an additional exhaust fan) is a good solution. But again, this creates more chances of dust accumulation in the nooks and crannies.
Going for a slightly positive pressuretraps extra air inside the caseand theairflow remains balanced.
Less Dust Accumulation
No matterwhere you’ve placed your PCand how clean your surroundings are,dust is unavoidable.
With fewer exhaust fans in a positive-pressure setup, all the case openings work topush hot air outside, including the dust nearby.
The intakefans directed towards the componentsare also usually covered by dust filters or perforated materials. So, the chances for dirt and grime to reach inside the chassis are quite low.
This is exactly theopposite when it comes to negative pressure. With fewer intake fans, the vents act as a vacuum andpull dust inside.
As mentioned earlier, too many intake fans with no or less exhaust is also not good. Since hot air won’t escape properly, thevital components, like the CPUand especiallyGPU may overheat.
The setup below withAIO has intake radiator fansthat create full positive pressure in the setup (so, less dust accumulates). However, with no exhaust fans, I experienced slight overheating when performing heavy tasks.
What about neutral air pressure? Well, it hasno impact on dust. So, leaning slightly towards thepositiveis the best bet to avoid dust.
Effortless Maintenance
Since less dust accumulates in a positive pressure setup, youdon’t need to frequentlyclean your PC.
The same case is with the cooling strategy that slightly leans toward positive. It requires less maintenance compared to negative or slightly negative air pressure.
Note:PSU fans are generally faced downwardsto suck cool air from outside the case. There’s aseparate exhaust fan at the rear, from where the hot air is thrown out. So, itdoesn’t affect the pressure and airflowinside the PC case.
Whether it be positive or negative pressure, the dust filters underneath the case andPSU fans are the ones to be the dustiest.
When to Go for Negative Air Pressure
The exact opposite of positive pressure is the negative pressure –less air enters the case and more is dissipated. This is the setup withmore number of exhaust fans than intake.
Excessivedust accumulationis the biggest reason you shouldn’t go for such a cooling strategy.
However, modern PC cases are equipped withdecent-quality dust filtersat the top and rear vents. Dust particles accumulate here before reaching the inside of the chassis.
While dust has become a less of problem these days, you still have toclean the fansand dust filters often.
Negative air pressure isbeneficial in terms of cooling the internal components. Theexhaust fans dissipate heat much more quicklyfrom the heated parts, which is the major con of positive pressure.
EvenSeanandNormfromTestedhaveperformed a smoke experimentclaiming that negative pressure isbetter in terms of hot air dissipation.
But with no/very few intake fans, the exhausts work against each other. Meaning thenearby vents/openings start to draw the same hot air into the case, affecting the overall airflow efficiency.
Opting for a slightly negative pressure is a great alternative. Just be sure to install the case fans properly and ensure there areno vents near them. This is usually best for thesmall form factor PC cases.
Differences Between Positive and Negative Pressure
Choosing the appropriate airflow strategy completely depends on yoursetup,environment, andrequirements.
To check whether your setup has the desired air pressure, you don’t need amanometer.Place your hand near one of the vents. If you feel that the air is blowing out, this means your PC enclosure has negative pressure.
A better alternative isusing incense sticks, likeJayzTwoCentsdoes tocheck whether his setup has balanced airflow.
Here are the main differences between positive and negative air pressure to help you choose the best one for your needs:
Final Things to Consider
Anyone who isexperiencing high temperaturesat all times should installone exhaust fan more than the intake(to achieveslightly negative pressure). But along comes the challenge of dust andfrequent cleaning.
Otherwise, neutral leaning towards slight positive air pressure is appropriate for most users. It leads to better airflow and less dust accumulation.
This is a never-ending debate and as I mentioned earlier, picking one completely depends on user needs and the components used.
Here are the other factors that should be considered for optimizing cooling and airflow:
