It is well known in the art that a variety of ventilating systems, which as an integral part thereof employ motorized inlet shutters, experience difficulty in operating in subfreezing climates, particularly with respect to agricultural applications such as barns in the northern climates. Great difficulty has been experienced with respect to the faulty operation of such motorized inlet shutters because of freezing of the individual blades of the shutters at subzero conditions. The cold weather inlet of the present invention, which can function either by itself merely as an inlet for outside air, or in conjunction with a powered tube ventilation fan, is provided with a single panel mounted for rotating movement within a frame, and an electrical defroster strip appropriately mounted in surrounding relationship with respect to the movable panel, and electrical controls for operating same.