Is it better to have a fan blowing on the pi or blowing out?
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I'm asking since when I got my 5mm fan with my case I have the fan positioned where it blows air on the the heat sinks. Now some forum posts said this was fine but others say fan blowing out is better. So is it fine to have air blowing on the heat sinks or should I change it?
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@redbatman Given that the Pi is so 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.
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Recieved wisdom is to blow the hot air out. But as the other poster said just having moving air is really good enough for a Pi.
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@redbatman blowing air out is best. If it is a hot day you dont want to be blasting hot air onto an already hot cpu.
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@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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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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Depends on how the air flows flow thru.
I prefer blowing out as dust does not settle as easily. -
Hmm well my case does have one ventilation hole.
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@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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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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Well to give a better understanding my case is one of those Zebra Virtue cases.
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@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. -
@ortsac
Good choice
I also prefer the bare PI and if I'm using housings then kinda that.
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@cyperghost couldnt decide on one flavor of pi? 😄
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I thank everyone for their replies.
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@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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Blowing on the Pi gave me best results
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@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. -
@xeon my case has holes at the bottom so it blows onto the arm CPU then the air goes underneath and out the case
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