Abstract: A packaged system for selectively (a) exhausting moist air from a shower stall while the shower stall is in use, and (b) drying the ceiling, walls, and floor of the shower stall after use. The system reduces the build-up of mold, mildew, and soap scum in the shower stall, and also reduces excess moisture in the building. A blower moves air through passages opened and closed by dampers driven by an electric damper actuator through a linkage of crank arms and connecting rods. The positioning of the dampers determines the air flow direction, and thereby the operating mode. A control switch starts and stops the system and also selects the damper position. A diffuser, connected to a duct, receives air from the shower stall in the exhaust mode, and alternatively directs drying air from a room air intake onto the surfaces of the shower stall in the drying mode.