each 1000 watts of light non vented needs 12000 btus of ac. In your case with 64 sq ft and 1600 watts theres two ways you can do this. 1. you could get air cooled reflectors and run a 440 cfm fan sucking air in thru a nextdoor room in the house seperate from the growroom cooling the lights and exausted to the attic or wherever,just not back into your room.This way youd only need a 12000 btu portable ac unit or make one yourself
Window AC converion for an enclosed space - 420 Magazine whichevers cheaper in your mind, but you gotta do the diy ac the right way or it will not work properly! If your planning on a sealed room id get a 2 ton mini split or a chiller pricey but worth it!Heat is a huge enemy! with the mini split you could run 2000 watts easy but you gotta add co2 to a sealed room!With all air cooled lights you colud run 4000 watts with 24ooo btu s hope this helps