Midi tower case with PSU at bottom - question

mikeymikec

Lifer
May 19, 2011
21,016
16,267
136
I'm building a PC using the Coolermaster Elite 335U midi tower case, which has the PSU sitting at the bottom of the case. I haven't built a PC with this configuration before, and I'm a bit puzzled by something.

There's a cooling vent directly underneath the power supply, and the screw holes for mounting the power supply allow for it to be mounted either way around (with its main internal cooling fan pointing into the case or into the bottom vent). I suppose the reason for the PSU to be mountable in either direction is to allow as many different PSUs to be compatible with this case as possible, but I would have thought that drawing air from under the case is blatantly asking for as much dust to potentially get sucked in as possible, and the computer has to be switched off and put on its side in order to clean the vent.

At least with the fan pointing into the case that with warm air rising, warm air from the rest of the system won't naturally be drawn into the PSU. On the other hand, warm air rising from the PSU HSFs would naturally want to rise, with the PSU fan pushing it back down again (and hopefully out). I suppose with the PSU at the top of the case and the fan drawing air from the case into the PSU would encounter a similar effect.

There's an extra chassis fan beside the rear I/O panel, FYI.

Not sure. Thoughts?
 

_Rick_

Diamond Member
Apr 20, 2012
3,981
74
91
Usually bottom intakes have (more or less) easily removable filters.
In this price league, these may be missing though. You could either create a DIY solution, by getting some mesh, a cardboard frame and some magnets, and fitting the thing, or just keep the environment sufficiently clean, that dust build up won't become a serious issue.
Inverting the PSU is probably going to add additional noise (still less than most graphics cards) and certainly is an option if the other two variants are too inconvenient.
 

Charlie98

Diamond Member
Nov 6, 2011
6,298
64
91
My rig is in a very dusty room (well... my entire house is dusty, but that is another subject...) and I just got magnetic filters like Rick suggested. Head to frozencpu.com for more choices than you can shake a stick at. They had a custom cut set for my HAF922... it really made a difference.

Next time I get a case... it'll have built in filters...
 

AUGieDogie

Junior Member
Jan 7, 2011
7
0
0
I have a bottom mounted psu ini my case. Air enters through the back with the downward exhaust. I have no more dust problems than i had with a top mounted pcu. Just blast some compressed air in it twice a year, same as you should with the top mount.

GL
 

blastingcap

Diamond Member
Sep 16, 2010
6,654
5
76
I don't have a bottom rear intake filter, so I bought a 120mm dust filter (would have gotten 140mm if not for cost) and taped it to the bottom. Cost $1.10. Be sure to seal any holes NOT covered by the filter with more tape. My PSU runs extremely cool sucking up cold, bottom-of-the-room air and does not have to deal with any hot air coming off the rest of the system. Only radiated heat would affect it.