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    Please do not post a support request without first reading and following the advice in https://retropie.org.uk/forum/topic/3/read-this-first

    Is it better to have a fan blowing on the pi or blowing out?

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    fanraspberrypi 3b
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    • chipsnblipC
      chipsnblip
      last edited by

      @thewinterdojer said in Is it better to have a fan blowing on the pi or blowing out?:

      o small, it doesn't make a difference, just as long as there is air flow you are fine. It may be slightly more efficient to blow the air out but I prefer to have air blowing in because it won't be sucking in dust and other things.

      i've tested both ways, and didn't notice much of a difference. idle temperatures stayed around 41-47c give or take (depending on time of day). as others have said, blowing the air out makes more sense, to avoid having dust collecting on the components and pcb. dusting the top of the fan every once in a while is easy enough

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      • O
        ortsac
        last edited by ortsac

        I prefer blowing the hot air out especially when the enclosure has ventilation holes elsewhere. The fan will draw the cool air in from those holes and blow the hot air out. Also, I do not want the hot air stay within the enclosure especially if it has no ventilation holes at all.

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        • XeonX
          Xeon Banned
          last edited by

          Depends on how the air flows flow thru.
          I prefer blowing out as dust does not settle as easily.

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          • RedBatmanR
            RedBatman
            last edited by

            Hmm well my case does have one ventilation hole.

            T XeonX 2 Replies Last reply Reply Quote 0
            • T
              twd Banned @RedBatman
              last edited by twd

              @redbatman in your case I'd use suck .... Nobody has addressed negative pressure if your case is sealed you will not be able to blow more air in than the volume of the case. If you use pressure to your advantage you can turn over the air inside many times more than blowing , and put less stress and less power draw. If dust is a issue fit a little filter cut a stocking up. But it's a pi so either way will work just sucking is more efficient in a sealed case

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              • O
                ortsac
                last edited by ortsac

                If the enclosure is totally sealed, then negative pressure will be an issue. But for the RPi, there will always be ventilation paths through the connection ports such as the GPIO area, camera port, LCD port, etc to release the pressure. Besides hot air rises, so it is better to blow the air out.

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                • RedBatmanR
                  RedBatman
                  last edited by

                  Well to give a better understanding my case is one of those Zebra Virtue cases.

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                  • XeonX
                    Xeon Banned @RedBatman
                    last edited by

                    @redbatman

                    Most people do, but you don't hear me gassing on about it.

                    "sorry could not resist"

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                    • O
                      ortsac @RedBatman
                      last edited by

                      @redbatman First of all, you ask for everyone's opinion, and we have given it truthfully. Now that I see the case that you have, it has plenty of holes on the side that can either disperse the hot air out or draw the cool air in, and therefore the preference is yours not ours. It is now a matter of whether you would want for the fan to blow dust into the heatsink or draw it from the vents.
                      Personally, I do not even use a fan or a case on my setup. The RPi is good without it. The fan will just present itself as another load on the power supply, and in the long run will just present itself as a mechanical failure. Also, an enclosure is just too constrictive.

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                      • cyperghostC
                        cyperghost
                        last edited by

                        @ortsac
                        Good choice
                        I also prefer the bare PI and if I'm using housings then kinda that.
                        img

                        edmaul69E 1 Reply Last reply Reply Quote 0
                        • edmaul69E
                          edmaul69 @cyperghost
                          last edited by

                          @cyperghost couldnt decide on one flavor of pi? 😄

                          cyperghostC 1 Reply Last reply Reply Quote 0
                          • RedBatmanR
                            RedBatman
                            last edited by

                            I thank everyone for their replies.

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                            • cyperghostC
                              cyperghost @edmaul69
                              last edited by cyperghost

                              @edmaul69 Well as are here some discussions that the future PI might be a bit faster (more CPU power, more GPU RAM....) this is the best soulution for now.
                              [IRONIC OFF]

                              This is just a picture from a store... Wasn't able to find one with only two layer :)
                              But these kind of cases works very well - don't look very ugly and provide good cooling.

                              Indeed I have one PI B rev1 still in use ... it's a little heatball.

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                              • R
                                RetroFreak89
                                last edited by

                                Blowing on the Pi gave me best results

                                XeonX 1 Reply Last reply Reply Quote 0
                                • XeonX
                                  Xeon Banned @RetroFreak89
                                  last edited by

                                  @retrofreak89
                                  It will. because the flow is aimed directly at the cpu sink.
                                  This is why i said it depends on the flow thru the case.

                                  R 1 Reply Last reply Reply Quote 0
                                  • R
                                    RetroFreak89 @Xeon
                                    last edited by

                                    @xeon my case has holes at the bottom so it blows onto the arm CPU then the air goes underneath and out the case

                                    XeonX 1 Reply Last reply Reply Quote 0
                                    • XeonX
                                      Xeon Banned @RetroFreak89
                                      last edited by Xeon

                                      @retrofreak89 said in Is it better to have a fan blowing on the pi or blowing out?:

                                      @xeon my case has holes at the bottom so it blows onto the arm CPU then the air goes underneath and out the case

                                      When it sucks the flow is spread over a large area.
                                      When it blows the flow is aimed directly at the cpu.
                                      So a larger amount of air hits and pushes away heat when blowing directly on the cpu.

                                      However blowing increases dust build up and sucking decreases it.

                                      Choose wisely.

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