Make sure you DON'T have the recirculating air on...make sure it's on FRESH AIR!!!!!!!!!!!!!! that's your biggest problem. second...to clean up your windows very quickly, with your heat/defroster on, turn on the AC and see how fast they all clean up. For instance, on the 6th gen cars, when you turn on the def. the AC automatically turns on. MAKE SURE TO TURN OFF RECIRC. AND TURN ON FRESH AIR!!