too fuckin hot?, 8x3x1= 24 cubic feet ,24cfm fan will remove all the air in your room in a min thus cfm (cubic feet per minute)i think thats right lol.

but i would look at some air cooled hoods if it was me,thats not alota room for a 400w
just do some tests before any plants are in there,high/low thermometers record your high temp for the day till you reset them.thier nice to have.

test before you fry , cuz i learnt the hard way:| good luck