What size fan do i need

ok the room is 8'x12' with 4 1000 watt lights what size inline fan will i need (how many CFM)JUST to cool the air cooled hoods.
any and all help would be great thanks..

With that many light you probably want at least the 10" inline fan(760fcm). BEst would be a 12" pushing 1050cfm
Heres one at HTG http://www.htgsupply.com/viewproduct.asp?productID=54455

and how do your come up with that number i just want to be sure befor buying one and it not being able to do the job right. and is there a thing as to much cfm where i will be just wasting my power?

just not into spending money i dont have to

ive hear something about you wanna recycle the air in the room every 5 minutes. but it might not of been 5. Just figure out how many cubic feet your room is. hxlxw and figure out how many cubic feet of air you need to move a minute to recyclye the air in 5 minutes.. someone correct me if im wrong. ill do a search now and see if i can correct myself.

in lights 1 Watt is equal to 3.423 BTU/hr. so 4 1000W lights is equal to 13,692 BTU/hr. To keep it simple and on the safe side. Take your BTU/hr and divide by 25. which will give you 547cfm. It can get way more technical and really if you do it right you dont even need that much. But that will keep you cool.