Conventional Intake/Exhaust Question: Air Flow Reversal?

thefallinglink · February 20, 2017

SHORT VERSION: Can/why don't people have air flow in their computers from back to front rather than front to rear?

Most air cooled computers that I know of use a front intake and a rear exhaust. I haven't built my own desktop before so perhaps there is something I am not aware of, but logically I can't make sense of this because most computers have their backs facing a wall. Why wouldn't you want the hot air coming from your computer to come out the front to blend more with the ambient temperature of the room? Otherwise the hot air goes straight at a wall, which can get very hot in close proximity to your computer. The opposite way, the direct vicinity of the computer remains cool.

So, either there is something crucial about air needing to go from the front of your computer to the back that I am not aware of or nobody has considered switching the direction of air flow, because I haven't heard any other talk on this subject. The closest thing I've heard would be both front and rear intake with top or no exhaust.

Any thoughts? Please explain if there's something I don't know, or if this would work fine but is less traditional.

PS: An afterthought, may be nice if your hands are cold you could just stick them in front of your computer

Timothy11 · February 20, 2017

It is louder and hotter for the person at the desk if you air comes out the front.

m0k · February 20, 2017

matter of convenience.

cases dont have any room for fans on the back because of the mobo IO and PCIe slots

cases have more area at the front for fans, and also dust filters are much more convenient to clean when theyre at the front of the case

Cyracus · February 20, 2017

hard to feed a gpu air when using the rear as an intake. I use the rear and top as exhaust, no external restrictions to airflow away from the pc except a wall ~7 inches from the back of it, doesn't make a difference if I move it away from the wall, yes I have tested, but yeah, should be a confined enough area that you could do rear to front if you really want, as long as you have a side intake to cool the gpu (or just don't have a gpu)

front and rear as intake leads to turbulence issues, accidentally had my rear as intake when I put my system together and once I turned it to exhaust system temps dropped ~10ºC

LogicalDrm · February 20, 2017

There are many cases with reverted mobo positioning which would allow intake from top/rear. Air inside case is moved mainly by fans, but outside its normal thermodynamics. Hot air rising and yadayada. So if your case would be confined or partially confined space, lets say under the table on on shelf, there would be much more air getting stuck around case. Wall near rear doesn't get that hot that it would be issue, its big surface and most of the time air around it is much cooler. But if there wouldn't be any fresh air coming from rear right next to wall, that would be bigger issue.

2 hours ago, Timothy11 said:

It is louder and hotter for the person at the desk if you air comes out the front.

Do you have any personal experience from that? Like how often you have case right in front of you blowing hot air towards you? The hotter part I can understand, so I'm more interested about how and why it would be any louder if fans are same.