allow for installation at a later date, although they are just as often used for new construction. A factory-built fireplace, often called a Zero Clearance Fireplace, is made up of a firebox enclosed within a steel cabinet, and a steel chimney or flue. They are built in such a way that they can typically be installed just inches away from combustible materials (hence the zero clearance). Most have glass doors, insulated walls, air-cooled pipes, and blowers that can move the heat produced by the fire into the room.