The DCS11 is designed for installation in a solid ceiling with 24" on center joists. A 13" depth clearance is required above the ceiling. After the DCS11 is secured to the joists, a finished molding is recommended for appearance. It is recommended that the air cleaner be installed in areas that do not exceed a 12 foot ceiling height. All filters on the DCS11 are accessible from the louvered doors on the face of the system.