Is there any point actually having exhaust fans?

[SafetySkull]

Since the pressure in a computer won't rise indefinitely in a set up with no exhaust fans, it must get to a state where the pressure remains high but constant. Which means that flow in = flow out. This then means that the positive pressure inside the case would act as the exhaust, pushing air out of anywhere in the case it can find a gap.

Doesn't this mean that you could get more air flow out of fewer fans by only having intakes? Am I missing something? Can someone explain this to me?

[ShadowCaptain]

Since the pressure in a computer won't rise indefinitely in a set up with no exhaust fans, it must get to a state where the pressure remains high but constant. Which means that flow in = flow out. This then means that the positive pressure inside the case would act as the exhaust, pushing air out of anywhere in the case it can find a gap.

Doesn't this mean that you could get more air flow out of fewer fans by only having intakes? Am I missing something? Can someone explain this to me?

 

Negative pressure is actually better for cooling (worse for dust though) - having more exhaust than intake means that cold air will be forced inside the case due to convection lowering the temps

 

Positive pressure is best in dusty environments as it will prevent dust being sucked inside as easily

 

Imagine a hot room - no fans means it will get hotter

Open a window so air can blow in - it cools down a bit but the heat has nowhere to go

Open a door wide, or open a ceiling vent - the room will quickly cool down

 

 

(Somebody correct me if I am wrong)

[ind3x]

Shadowcaptain is right, but it also depends on the case.

For example, i have the 230t which has an open honeycomb top. I have 2 fans in the front as intake, and only a single exhaust in the back where my h80i sits.

The heat from my CPU is directly ejected out of the case, and the GPU heat rises and flows freely out of the top vents.

Putting two fans in the top would actually probably take performance from my CPU cooler.

[rentaspoon]

If you have a fan pulling out air it will define where the air exhausts as its the place to exit with least restriction.

[othertomperson]

That's what I did with my HTPC. Put all the fans inside a some tights as dust filters, had them all intaking and the heat leaves though the mesh gaps in the case. It's not a remotely heat-generating beast though, it's just a Pentium using its iGPU so I'm not saying do this with four 290Xs or 480s or something

[LogicalDrm]

I personally like neutral or close to it. You get less dust but temps are better than higher positive pressure would give. And you can manage it with less fans.

[rupertsilva10]

It does help. Proper air circulation helps your computer maintain just the right temperature. There are many hardware issues that we experience just because of too much heat!