so my room is 10x12x9 and im trying to figure out what size intake or exhaust fan i would need. from what i have read you multiply LxWxH to get cubic volume of room. so that would put my room at 1080 cubic feet, so if i wanted to cycle the air in the room 3 times per minute i would need a 3240 cfm fan? If thats correct, is there fans with cfm rating that high cause i cant see to find one online, or would i need more than one intake fan..............i think i doing something wrong