MrCool has a DIY cassette that is designed to fit between residential joists: https://mrcool.com/diy-ceiling-cassette/ https://mrcool.com/diy-ceiling-cassette/

MrCool has a DIY cassette that is designed to fit between residential joists: https://mrcool.com/diy-ceiling-cassette/ https://mrcool.com/diy-ceiling-cassette/ No idea if it's any good though, and I don't really like the big logo and big black IR receiver.