Help me decide on fan placement...

[BoundByBlood]

I have a steel tower case pre-fitted with 3x120mm intake fans in the front and 1x140mm exhaust fans in the rear.

Along the top of the chassis is an expansion slot area for more fans. I have 2x120mm spare fans (they have pretty decent static pressure) and I think I might have been experiencing an issue of heat buildup inside the chassis so I'm wondering in terms of airflow would it be better to setup these fans as intake or exhaust along the top?

Having five intake fans and one exhaust seems a bit imbalanced, but if it helps with airflow I'm willing to try it.

So I ask you, if you were me how would you implement the fans?

 

[Mr.Scott]

Easy.
Exhaust = back and top
Intake = front, side, and bottom when available

 

[EarthDog]

Exactly... front/sides = intake while top/rear are typically exhaust. This creates good airFLOW. I prefer more exhaust than intake, but others prefer more intake than exhaust. About the only thing that is PROVEN between those two methods is that more intake that exhaust, assuming the intake is filtered is that it let's in slightly less dust (won't come in through the cracks).

Make those up top exhaust.

 

[mokrunka]

Also, be careful about using the bottom of your case for intake--if it's on carpet, it'll be like cleaning dryer lint from the filters/fans.

 

[Ivy]

There is no reason putting a PC on a carpet. Naturally, strongest airflow is down to up direction, but the smallest amount of dust is up to down direction (this is how i have my airflow done, some cases are good doing it). On PCs with sufficient airflow, fighting dust is more critical and the direction of airflow may not always matter. Positive pressure can reduce dust but will decrease airflow. I think every case may have different approaches, there is no general rule. Most important it still to have quiet coolers, else it will certainly never be fun...

 

[ATMINSIDE]

There is no reason putting a PC on a carpet.

Actually, there is. Where does it go when your desk is full and the computer room has carpet?

 

[Dalchi Frusche]

Actually, there is. Where does it go when your desk is full and the computer room has carpet?

On a custom built box of course Just teasin, I've had to put a computer on carpet before. Just stuck with front intake and things went well with very little carpet lint/dust being sucked in. I had a friend throw two reams of paper under his case before to elevate it slightly.

 

[ATMINSIDE]

On a custom built box of course Just teasin, I've had to put a computer on carpet before. Just stuck with front intake and things went well with very little carpet lint/dust being sucked in. I had a friend throw two reams of paper under his case before to elevate it slightly.

I used to put mine on a few layers of foam board that was cut to match the size of the case, but it was still on carpet.
Used the same ideals with airflow though, no bottom intake.

 

[Mjolnir]

I really don't feel like you'd get any better temps with an extra couple fans? 3 in and 1 out should already be enough, unless there's some pocket near the top that might get alleviated..

I had my computer on a carpet for a while when it was M-ATX/ATX but I used a plank of wood from am old desk to put it on so it wouldn't be directly on carpet itself, though still gathered a reasonable amount of dust.. Even now with it off the carpet I still get a lot of dust.. My rooms carpet is pretty crap for that XD.

 

[BoundByBlood]

Thanks for all the replies.

So here is how I currently have it all setup: My chassis has two removable dust filters, one on the front and the other on the top. The front has 3x120mm intake fans, 2x120mm exhaust on the top and 1x140mm in the rear. I have see through panel on the side, but there isn't an intake slot for a fan.

The case is also setup for either a top or bottom mount PSU, currently I have a bottom mount with the PSU fan venting through a grate out of the bottom. I could do a top mount, but the two drawbacks are (1) I would lose one fan exhaust slot on the top and (2) the grommets for cable management aren't designed for a PSU up high.

I'm contemplating on refitting my PSU up top and using the bottom for an intake fan, but the bottom grate doesn't have screw holes to hold a fan. I could rig it to make it work, but I'm not convinced it's worth all the trouble rewiring the PSU when the cables stretch too much and the grommet holes are too small when it sits up top.

Oh, I also have tile floor btw.

 

[Mr.Scott]

Leave the PSU on the bottom.

 

[Mjolnir]

+1 keep at bottom. IMO, 1 rear exhaust, 1 top exhaust, 2-3 intakes as you have. Done...

For me personally, for smaller to mid cases 2 intakes and 1 exhaust (assuming 120-140mm) is enough. Larger cases 2-3 intakes, 1-2 exhausts. Full towers perhaps 3-4 intakes, 2-3 exhausts? But I really don't think in that last one that anymore than 5 will warrant any reasonable temperature gain.

 

[Mr.Scott]

3 intakes, 3 exhausts.
I prefer more exhaust than intake also.

 

[Mjolnir]

3 intakes, 3 exhausts.
I prefer more exhaust than intake also.

I'm opposite but primarily for dust reasons.. XD