to get the humidity down you need dry air,at this time of year i block up my air intake from outside an an let the growroom suck air from inside the house.i've got a 5" extraction system run by a 8" inline bell fan attatched to a 10" carbon filter,so the room stay's at 75 degree's an the humidity is 47%,ideal as mine are 4 week's into flower,the problem with the humidity being above that is it encourage's bud mold(nightmare)but when in veg growth the humidity can be as high as 80%,hope this helps ..love an respect..spliffbuilder.