No the garage is always clear, also, the ducting will be insulated preventing hot to the touch plus some of the sound, also the fan will be in a box lined with recording studio foam like you suggested, not to meantion I can take a few other precautions to hide it if I need to.

See the garage is no longer really a garage, its been converted into a extra room, huge and not accesable from inside the house, it has a seperate door outside, its being used as a storage/smoking room actually lol, it also stays locked when no one is in there. I just dont want the grow box out there.