Ice shaping inside windshield??

Hello guys, we drive a black up of 2013. Last time it happens often that we have to make the outside of the windshield also the inside of the windshield ice-free. How can it be that the car gets so wet from the inside? We have no sliding roof and the floor mats are m.E. also dry. Older vehicles of VW (golf and co) used to have the foils under the door panels where water would come through. Does anyone have an explanation / solution? much read and found on the Internet but no solution yet!