Stacking pc fans??

I am currently using a 100 cfm pc fan that I cut a hole for in my closet roof. This fan was perfect for the 4'x3'x10' area I am using, at least until my perpetual garden gets off and running. I have run (4) 4' florescent tubes with no problem with heat. I am about to be running those tubes as well as my 400 watt hps. I did a test run for a couple hours and the temperature went up to 90 f. W/o the HPS running the temp stays at a respectable 82 F day and night and I live where it is almost always 100 or better all summer.
I dont really want to cut another hole...but i have at least 4 more fans of this size...could I stack them ontop of one another to boost my cfm and keep the room cooler? Shoot me some ideas guys...i Love this site and have gathered solid info.

Hi there friend!

I had a "closet", 45cm wide, 45cm deep and 90cm high and was using only 1 125w cfl, and using one 100cfm as an exhaust.. I had a litle heat-problem and tried to stack two more on this one I had.. I found no results. I didn't have a fan to blow in, but had some holes at the bottom.
The second I put an intake- fan at the bottom I saw difference in the heat, it lowered.
If you dont have an intake-fan, I would suggest you at least try that, but I think you need a bigger exhaust fan...

But I'm no expert
this just worked for me

with a space that small im sure heat was an issue. i cant put an intake in the room unless i cut the door and thats not an option. i guess i'll just break down and buy a bigger exhaust fan

Stacking fans won't increase cfm. Also pc fans aren't very efficent and when your plant starts to smell what are you going to use to scrub the smell? honestly your betst bet if money allows is to buy a tent, carbon filter, fan and maybe an aircooled hood or cool tube.

everything mr2shim said, ive had pc fans kick my ass more than once! the only thing they're good for is redesigning your growroom ventilation system mid-grow!