Positive Air Pressure?

[Cs342]

If my front fan is meant to intake air and both the rear and top fans are meant for exhaust, then how is positive airflow even possible in a regular case unless I install fans on the side and in the bottom of the case or switch the top rad fans to intake? So many people swear by positive airflow, yet it isn't even able to achieve more intake fans than exhaust fans unless you force cold air down the top of the case instead of letting hot air rise. In most cases there is only room for 1 front intake, 1 rear exhaust and 2 top exhausts, making the air pressure negative.

[flibberdipper]

Make the rear exhaust an intake so you have neutral pressure.

[Enderman]

Also make sure that all your intakes are filtered otherwise positive airflow is useless.

[kcchi]

what @tmcclelland455 said, and i might be wrong but don't cases usually have 2 front fans slots? That's the kind of image i have

[Cs342]

So I'd have to buy a fan filter for the rear fan? Is it really worth doing that just to get positive pressure?

[airdeano]

something to ponder:

 

if you use an air filter on the intake fans, it suddenly reduces the amount of air

brought into the case. if fans are the same..

2 filtered fans and two exhaust fans is still a negative pressure scenario

3 filtered fans and two exhaust fans is still going to be a negative pressure course.

 

can pretty much count on 4:1 to make an equalize pressure case

[LogicalDrm]

Just amount of fans doesn't make anything. If you truly want to know what airpressure your case has, you need to know CFMs for both intake and exhaust fans. So basicly you can modify airflow in cases that have limited mounts for fans. Like make intake have more CFM by running them full speed or higher speed than exhaust ones.

[Shaqo_Wyn]

If my front fan is meant to intake air and both the rear and top fans are meant for exhaust, then how is positive airflow even possible in a regular case unless I install fans on the side and in the bottom of the case or switch the top rad fans to intake? So many people swear by positive airflow, yet it isn't even able to achieve more intake fans than exhaust fans unless you force cold air down the top of the case instead of letting hot air rise. In most cases there is only room for 1 front intake, 1 rear exhaust and 2 top exhausts, making the air pressure negative.

Positive or negative air pressure is about total intake CFM vs total exhaust CFM. Two 140's intake vs two 120's exhaust, would generally mean higher intake CFM. Most cases I've looked at have 2 or more front fan mounts, 1 or 2 bottom fan mounts, 2 top fan mounts and 1 rear fan mount. This is more enough flexibility to setup positive air pressure.

[airdeano]

might be helpful:

 

[Rekx]

might be helpful:

http-~~-//youtu.be/4NYHC3DXynM

This :-)

[Judist]

fanspeed

[spwath]

something to ponder:

if you use an air filter on the intake fans, it suddenly reduces the amount of air

brought into the case. if fans are the same..

2 filtered fans and two exhaust fans is still a negative pressure scenario

3 filtered fans and two exhaust fans is still going to be a negative pressure course.

can pretty much count on 4:1 to make an equalize pressure case

This.

My case has very restrictive filters (I added carbon filters from an air purifier) and I have 4*120 intake, and 2*120 exhaust and dust gets in, not though the filters tho, the slight negative pressure.