What size exhaust fan help?

i have 12x12 room and would like fan size ideas. i will be pullin air from room through carbon filter connected to Y going to 2 rows with 2 1000 watt light hoods in each row with Y connector at end going to fan an exhausting out window . whats a good size fan for the job ? im tryin to exhaust room and lights at same time

with that setup I would get the biggest most badass fan I could afford. look for high CFM ratings.

you could use this calculator http://cheaphydroponics.com/Merchant2/cfmcalc.htm

based on that calculator I'd try finding something in the 500 cfm range...