2nd fan blowing in or out?

[Jhill]

I have a second fan for my machine that I'm going to install on the back of it. Should I face it to where the air is blowing in the case or out the case? I was going to install it to where the air was blowing out but then someone told me alll the fans should blow in the case so ALL the air can blow out of the PSU fan.
Thanks for any help

 

[Amused]

You should have the fans in the rear blowing out, and the fans in the front blowing in. This creates a "wind tunnel" effect and moves air through your case efficiently.

Your power supply should not be the only fan blowing out, if you have two fans blowing in.

 

[Yossarian]

I'll second that.

 

[4824guy]

Yes, One blowing in and the rear blowing out. Technically, it would be most efficient of the air pressure in the case was the same, by having the fan blowin in moving the same amount of air as the one blowing out of the case. When all that happens, you get the max. cooling and airflow.