With a remote control for convenient adjustment, this double window fan draws in fresh, cool air from the outside or exhausts stale, hot air from inside. It can also do both simultaneously, because each of the two fans can be set independently to draw in or exhaust out, allowing the unit to exchange inside and outside air. Operable either manually or automatically, with its programmable thermostat turning the fans off and on to maintain a selected temperature--the unit has three speeds, electronic controls, and an LCD screen showing the selected temperature and the room temperature. The twin fan is designed to fit double-hung, vertical-slider, and casement windows. Overall, the unit is 13 inches high, arrives fully assembled, and carries a five-year warranty against defects.