Window and wall air conditioners are self-contained units for cooling a single room or small area of a building without taking up floor space or requiring connection to ducts. They're typically used for seasonal cooling or for supplementing central AC systems. Window or wall units with heat provide cooling and heating from a single unit. Window units fit through an open window─usually a double- or single-hung window─and can be removed and stored when they're not needed. Wall units permanently install through a cutout in an exterior wall using a wall sleeve that provides proper support and creates an airtight seal, which makes wall units more energy efficient than window units. Use accessories for mounting, protecting, and maintaining window and wall AC units.