Should the fans at the top of the PC case blow air out or in?

[adreno420]

is it okay for top fans to blow air in the case?

 

[madmatt30]

No , top fans should always exhaust.
Natural convection always carries warm air to the top of the case , you're actually forcing that warm air back into the case.

 

[13thmonkey]

Second person today like this, I don't buy the convection argument personally, the slightest fan speed will override it, but it's more important that you get flow, you need air to be changing in the case on a regular basis, about every couple of seconds. It's been tested and in at the front/bottom and out at the back/top is best. It gives the GPU nice cool air to work with, and the CPU cooler gets some too.

 

[neiler0847]

You cannot argue the fact that hot air rises. If you blow hot air out the bottom, it's just going to rise around the case, with a potential effect on your ambient temperature (you might even end having your intake fans suck the warm air back in).

So you can't beat top exhaust.

However, if you don't care about noise, then you can get fans to blow hard enough to make the air do what you want.

 

[13thmonkey]

i don't argue that hot air rises, merely that with the heat sources involved that hot air rises strongly enough to be overpower all but the slightest of encouragement by a fan. As to sucking it back in, in a perfectly still room, perhaps this would happen.

 

[w1418826]

I was looking this up too because I know hot air rises but people also say where there is dust filters the fans there should be intake so good to clarify.. but should I remove the dust filter then? I'll have two intakes in the front, an exhaust in the back and at the top of the case. will this be a good setup for continuous cool air for the system?

 

[neiler0847]

I was looking this up too because I know hot air rises but people also say where there is dust filters the fans there should be intake so good to clarify.. but should I remove the dust filter then? I'll have two intakes in the front, an exhaust in the back and at the top of the case. will this be a good setup for continuous cool air for the system?

Which dust filter are you talking about, the top? It can be useful to have a top dust filter, even if that is outbound air, to stop ambient room dust from settling into the case when the machine is off.

There are no wrong answers. Experiment. Get the temperatures you want and monitor the buildup of dust, if any, inside the case.