Unlike window units or hotel style units, which require a large wall or window opening to be cut, Mr. Slim only requires a three-inch round opening. This opening in the wall is necessary to allow the refrigerant lines and the wiring to connect the indoor unit to the outdoor unit. This opening is sealed and insulated by your installing contractor so no drafty air leaks or water from outside get in. An example of how the lines extend from the back of the indoor unit, then through this opening, is found below.
