How should i insulate my case?

[4od]

I recently began using a ducted airconditioner to make my case super cold, but i feel like theres a huge amount of power being wasted by all the cold air that leaves the case. Would it be possible/sane to try to insulate the case to keep the cold air in, and just have like 1 or two exhaust fans? (prob psu)\

More info on the setup here - http://www.ocforums.com/showthread.php?t=487529

Theres also a big vent on the side of the case, which still has a 80mm installed from my days of air-cooling that i never bothered to remove

 

[Diggrr]

I built my case using foam cored poster board I found at walmart. It's a 1/4" thick, 2' x 3' with both faces covered in white paper.
The paper makes it easy to glue into place if need be, but use white school glue because some glues will melt the foam.
The paper also helps in cutting down on the static electricity you would get from plain styrofoam/blueboard/pinkboard....something to be concerned with.

Leave the 2 vents in place, all that air has to go somewhere, and the psu can use that cooling too with an OC load.