We are adding a 220 sq. ft. bathroom off of our Bedroom. We will have a pass through doorway. I am adding a 12,000 BTU LG 26 seer mini-split ductless system over the doorway between the bath and the bedroom. I was considering using closed cell foam under floors, in walls and on vaulted roof. I woke up this morning wandering if that would create a humidity problem in the Bathroom or if the ductless system would act as an air exchanger, eliminating humidity concerns. We have lots of windows in the bathroom but prefer not to open them in the winter time for obvious reasons. We have a conventional heat pump AC in the rest of the house. We live in Georgia where it can be hot with lots of humidity. I appreciate your thoughts and ideas....