Does the PSU fan blow in or out?

[tigersty1e]

I'm planning on putting one more fan on my case, but I want to maximise the airflow.

Does the fan PSU blow air in or out?

What's more important... blowing air in or out?

 

[idiotekniQues]

if a ps has one fan it is acting as an exhaust.

if it has two the one on the outside of the psu is an exhaust, the one on the ps that is inside the case will be an intake usually.

if you had to choose one thing, intake our exhaust - exhaust is the way to go. the act of sucking air to go outside the back of the case will draw air from the front vents of the case thus creating airflow.

 

[Zardnok]

Originally posted by: tigersty1e
I'm planning on putting one more fan on my case, but I want to maximise the airflow.

Does the fan PSU blow air in or out?

What's more important... blowing air in or out?

What case do you have now? How many fans do you have in it? What type of fans do you have? Where do you plan on placing the "new fan"? Do you have a fan controller?

Most PSU fans suck air from inside the case and exhaust it out the back of the case.

As for which is more important, as a general rule, you want to have a slight positive flow to keep the dust out of your machine. This means having slightly more intake than exhaust. You need to be careful to not disrupt the interior flow of your case. Sometimes adding a fan in the wrong place can create turbulence inside the case and increase the heat level.

Your question is difficult to answer without knowing your exact configuration though. Please give more information so we can make the proper recommendations.

 

[Zepper]

Most PSUs take air from inside of the case and move it to the outside (in hopes of carrying some heat away with it) thru the rear of the case.

If you have only one fan and have to choose whether to use it as intake or exhaust, then use it as exhaust as that will have more effect on the temps within your case. Assuming enough fans to do what you want, then all you really need an intake fan for is to assure that some air gets directed to your HDDs. As long as there is enough venting at or near the front of the case that the exhaust fan can breathe fairly easily, that's all you need. But beware of extraneous venting like on the sides or in the top or bottom as that will limit the effectiveness of your airflow as it will "short-circuit" the air flow being drawn in there and right out thru the exhaust whilst doing little or no work along the way in the way of absorbing and carrying away some heat.

I like to set up a positive pressure environment (total CFM in a bit > total CFM out) in my cases so a good intake fan has more of a role in that scenario - and a fan controller for balancing in and out. Done properly P-P can keep a lot of dust, pet hair, etc. out of your case while not sacrificing much in the way of cooling or sounding like an industrial wind tunnel.

.b.h.