I believe that they make them to fit into an open window (not a door). I don't have a suitable door to put one in because I have glass storm doors on both of my entries. I haven't even started researching this yet, but I guess you put it in a window that you don't mind "giving up", as it would be like a window airconditioning unit and be there all the time. I'll let you know if I ever get that far!!