Stinkyattic- today I will switch out my fans and add some insulation around the duct. Thanks for the tips! I had a hard time understand what "Remove all obstructions from the passive intake and make it twice as big as the total exhaust hole size, including the exhaust from your light." Maybe I am just stupid but it just didn't click to me. All of my exhaust goes to the outside of my house and all my intake comes through the entry space into the attic (grow room) from the house. Should I be pulling and sending it to some place else? I wouldn't do it like this if I had a spare room to grow in but I'm stick in an attic. Thanks again for your help and time.