THE CONTROL DEVICE DISCLOSED HAS A DECORATIVE ENCLOSURE SUITABLE FOR WALL MOUNTING. THE FACE PLATE OF THE BOX-LIKE ENCLOSURE IS SEPARABLE FROM THE SIDE WALLS BUT IS RECEIVED INTO THE WALLS SO AS TO PRESENT THE APPEARANCE OF A UNITARY STRUCTURE. THE FACE PLATE IS REMOVABLE TO GIVE ACCESS TO THE INTERIOR OF THE BOX TO SECURE IT TO THE WALL OF A ROOM BY USING SUITABLE FASTENING MEANS AND ALSO TO PERMIT WIRING THE CONTROL DEVICE. THE FACE PLATE CARRIES THE CONTROL DEVICE PER SE AMD THE FACE CAN BE MOUNTED ALONE ON THE SURFACE OF A DUCT WITTH THE CONTROL DEVICE INCLUDING A SENSING MEANS INSIDE THE DUCT.