Case fan - pull or push?

[Brazos]

I'm building a pc for a friend. Of course the power supply has an exhaust fan. There is room in the front to add a 2nd fan. Should that be pulling in air (to create a positve pressure)? Or another exhaust fan (pulling out air)?
My gut feeling says to pull air in but thought I'd check with the experts.
Thx

 

[twong82]

The fans in the front pull air in and the fans in the back pull air out.

 

[Viperoni]

Exactly what twong said.
You want all your airflow going in 1 direction.

 

[toph99]

what they said

 

[Siamskunk]

That's right, 1 direction. Front pulling in and Back pushing out is the most common method.

Which mean you can have back fans pulling in and front fans pushing, might sounds obvious but it also works.

All in all, you have to some experiment 'cus all cases are not made equal.

 

[jhites]

Like everyone said, front lower fan pulling cool air in and top back pushing air out. Check the P/S fan to be sure it is not a smart fan (only turns on at certain temps). You want to balance the amount of air in and out to get good flow.

 

[cipher00]

Ditto. Most rear/out fans are "high" or should be (sometimes space requirements make ppl do odd things to case positioning) since heat rises. Front "low" fans help get the circulation going...

 

[jawaki]

Same as all the above

 

[5mudge]

Now the question is: What percentage of PCs are incorrectly built with respect to fans?

 

[micron]

5mudge, alot.

 

[ericd]

When I was in college way back in 99 I saw one guys computer that was a FULL tower and he obviously had gotten in his head "more fans the better" I think this thing had like 9 or 10 80mm Sunon High outputs.....all blowing into the case. You could hear the fans straining from accross the room. He couldn't figure out why his processor kept overheating. The side of the case practically blew accross the room when you took it off while the fans were running.....not really but you know what I mean. It was almost too hard to make hime feel like that much of a moron by telling him....almost. Still don't know what case that was, no case I have seen before or since has ever had that many fan mounts....and he didn't have to cut any of them.

Eric