Side panel fan: Blow in or out?

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Lance

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We started discussing this in another topic, I decided instead of hijacking I should make a new one.

Should the fan on the side of the case blow in or out? I have mine blowing out; the reasoning being that it's actually below my graphics card, and the air from my GPU fan doesn't really have anywhere to go (there is a vent in the next PCI slot, but I don't think that's all that effective). Especially if I had another PCI card right next to the fan, there would be a lot of hot air trapped that wouldn't get out very fast.

Most people seem to have theirs blowing inwards, claiming that it improves airflow, but at least with my layout this doesn't seem like it would be all that effective.

Discuss; I may try both ways and actually see the temps by the numbers.
 
I think you're right, it's pretty dependent on the layout of the case. I have my side fan level with my GPU and it actually runs hotter with an inward flow, whether my rear fans are exhaust (tried for the vacuum effect) or not. I would definitely try both ways. how many case fans do you have anyway?
 
My side 120mm is directly next to my HD4890, and I've got it blowing in.

I've got two 120mm on the front as intakes, the one on the side as an intake, and then one just a little above the video card on the back blowing out - as well as two top 140mm exhaust fans. The side of the room that's maybe 5 feet from the side of the case with the window and intake fan is also the side of the room that has the air conditioning vent and/or windows if they're in use. So that's where the cold air is coming from. It really helps to pull in that cold air from the side and front, and then blow the hot air from the inside of the case out of the back and the top. The PSU is also on the bottom in an upside down layout, and so that hot air's being forced upwards as it is.

I think it's really entirely dependant on the case layout as a whole as has been said. In my particular instance, with 4 120mm fans and 2 140mm fans, a side exhaust won't help me much.
 
Well, that was a boring experiment :D there was only about a one degree difference which could be easily attributed to different workloads (although I tried to keep things the same).

So in my case, the actual flow is pretty much unaffected. I'll leave the fan blowing out, since there's less dust to worry about. :P I suppose it makes sense - not accounting for actual movement of air, if you take heat out things run cooler and if you bring cool air in... the heat just goes out another way with the same result. In my case (pun intended >_>), it happens to be the pretty much the EXACT same result.

Since my side panel is already off, for my personal results I'll try with no side panel and with just no fan.

I have to admit, I enjoy experiments, even if they're as lame as this :P
 
I wouldn't recommend having the case open with the side panel off because the air flow has no direction and will actually just drift out of the open side. You wont feel it but it will. The hot air will still get out as normal but it will not get cool air going in as strongly as it is if the side panel was closed.
 
Clarko said:
I wouldn't recommend having the case open with the side panel off because the air flow has no direction and will actually just drift out of the open side. You wont feel it but it will. The hot air will still get out as normal but it will not get cool air going in as strongly as it is if the side panel was closed.
Click to expand...

Probably not, but it's not anything long term, I'm just messing around seeing what the temperature sensors are saying.
 
do something for me. turn the fan off and see how that effects things. My guess is that a side fan does nothing at all, and is pretty much unnecessary.
 
It depends on the layout of the case. The tempest has the side panel intake fan. Whichever works for you.
 
Fans work best in tandems; have one main 'outbound' fan (preferably in the rear) and multiple 'intake' fans. I like to put intake fan(s) in direct airflow over the HD array, the graphics card, and the CPU. Just blowing air into your case isn't enough; you need the continuous airflow to really do a good job of cooling your stuff ~
 
Ryken said:
do something for me. turn the fan off and see how that effects things. My guess is that a side fan does nothing at all, and is pretty much unnecessary.
Click to expand...

Gained about 3 degrees, if I'm remembering all the numbers right (and there wasn't something else causing more heat). So it made a difference, but 3 degrees (even celsius :P) is almost nothing - so it wouldn't really be worth it to buy a fan unless you have a clever way of making it cool things better, but if you have an extra (like I did) you might as well throw it on, it shouldn't hurt.

Also, the airflow in my case sucks anyway because my graphics card pretty much divides it into two sections, so it's more a matter of direct heat transfer. I would like to get a better exhaust fan for the rear (using the one that came with the case right now and I just have a cheap case... my stuff runs at nice temps anyway, I'm just doing all this to learn more about the air cooling process), as I think that would help pull the air from the front all the way over the graphics card to the rear.

So altogether, I have a front intake fan+rear and side exhaust fans, along with the PSU, CPU, and GPU fans... so I have hot air going in all directions, but by some miracle they all lead out.

TL;DR: Side fans make a negligible difference, at least in my case*.

*there's that pun again.
 
well its somewhat dependent on your layout but here are the basics.
The air blows in from the side fan, in from the front fan. This airflow basically covers all of your components and parts, HDD, MOBO, GPU, CPU, etc..
Then the top fan and the back fan pull all the hot air out of the case after it has touched all your components to cool it down.
With your setup, when your air comes in from the front, it begins to get pulled out already by your side fan and it basically disrupts the airflow. The air coming in doesnt reach all the parts in your case and gets blown out too early.
You are virtually pulling cool air out of your case when you want it in.
Basically it doesnt matter if your fan is directly over your GPU or anything its just that airflow direction that matters, as long as your GPU fan is sucking in COOL air to cool down the card then your fine.
I would change your side fan basically to get the air coming into the case rather than out, if the way you did it was more efficient, there would be a case out there that actually does it but there isnt.

I have a 230mm fan on my side panel, well actually all my fans are 230mm except for my back fan which is 140mm. I have a cooler master HAF 932 and its airflow is amazing.

Im just letting you know that if you have air being pulled it with the side panel, i wouldnt expect crazy temperature drops maybe like 1-2 C here and there but thats it. If you want real temperature drops, get an aftermarket cooler.
 
The 'theory' in this situation is mostly science based. Although it doesn't always work in practice, the idea is that you have more fans blowing air out than sucking in, resulting in a minor drop in pressure in the case, pulling more air in through the front of the case. This increase in air flow = a cooler case. ie. back = blow, front = sucking, side panel should really be blowing, but whatever balances it out best.
 
It depends on the case, and your graphics card. I tried it both ways on my Antec 1200, and got slightly better temps with it blowing out. The GTX 295 exhausts some air to the side, so it may be different for other cards. I ended up doing a side panel window mod on my case so now there isn't a fan at all there. I noticed a 1 or 2 degree gain in temps, but I can compensate for it with fan speed.
 
yes my fault....i guess i didnt mention about the whole pressure being less inside the case on this thread but i did mention it on the other thread....u do want less pressure inside the case so that more air rushes into the case as iGreen said.
 
I've got one 120mm outtake fan over my CPU, and it stays pretty cool while OC'ed 500MHz, it idles 30-35 and gets up to 40 most while under full load.
I've got another 120mm as intake over my 4890 and its temp fluctuates between staying cool and getting up there hot. I've tried it as an intake and outtake over the GPU and it hasn't made a big difference either way, but I switch it every now and then anyway.
 
I don't know if it is true or not but some people say they get better temperature results (barely) by not installing side panel fans because they say it sort of messes up the flow from the front intake fans to the back or top exhaust fan, I don't know if this is true but I have seen it around a couple forums.
 
I havent really read many of the replies to this thread, cause they lost me when they started talking about air pressure differences and what not. But, i can tell you from first hand experience, it would be better to have the fan blowing out.

As a general rule for the standard rectangular PC case, you want the air blowing front to back, bottom to top, and right to left (Assuming your motherboard is mounted on the right side of the case, as most are). Dont ask me why, i dont know. Ive tried countless different airflow configurations and the one I just mentioned always works the best for me.
 
Adding a fan just makes more noise. If you already have 3+ fans there is absolutely no reason you need a 4th on the side window. Just my opinion
 
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