http://3tonairconditioner.net/air_conditioner_for_casement_windows.html has more on: Locating The Right AC Units For Casement Windows When you are dealing with those narrow and high sliding windows or slider windows, like those in toilets, you will need a narrow and tall window ac. Often times, the restroom will be the spot that demands air cooling and dehumidifying the most. Casement AC unit, or a sliding window ac unit is suitable for horizontally sliding windows, as slim as 15 inches wide, and may be used as an further ac unit to supplement a central ac unit, or it could be used as the stand alone unit. What To Be Careful About When Searching For Casement Windows AC Units