We installed this through wall AC unit at a condo complex we have a lot of experience with, it is our 10th installation here. This complex is challenging as it has an old style 23″ wide AC sleeve, through wall AC’s are now made a universal size of 24″ wide so obviously a new AC would not fit in the old sleeve, modifications had to be made. After removing the old sleeve we then opened up the wall in order to accommodate a new 25.5″ wide AC sleeve. After installing and sealing the new sleeve the AC was installed and levelled (1/8″ slant to the outside for drainage). This is the finished project.