I'm moving in with my boyfriend potentially, who lives in the basement of a house shared with 3 other boys. All the other boys live upstairs and one has a cat allergy. Every now and then, the boys are all downstairs in a room remodeled as a "band room" for band practice. The entire basement is tiled and the cat would only be allowed down there with the exception of the "band room". The main floor and basement share the same central air conditioning system. My questions are: Will my boyfriend's roommate suffer from the airborne allergens potentially transmitted via airconditioning even if they must travel upstairs to reach him? And if we restrict the cat from the "band room", will the roommate's allergies still somehow suffer while he's practicing in there?