I don't know what a open or closed system is but I will say that I want to have an AC and run exhaust out of the room. Can I do that with intake fans going to my attic? Also can you use that T-5 for whole process, start to finish? man, You are awesome!! I don't know you but I think you are so friggin awesome. Thank you for taking the time to tell me all this stuff. I can compensate you for you information if you would like because I really need this coaching.