In the sliding door I have a fixed large window and I can only ventilate with open sliding door, but this is not very comfortable when there are a lot of insects, in particular midges. I have a screen in the back of the camper and in the roof, but when there is little wind and it is very warm, this is not enough for sufficient ventilation. For almost every van there is a fitting screen door on the market, especially for Fiat Ducato, which is very popular. It means you have to be very precise and be strict regarding the measurements of the door opening and if you have an isolating floor, you have to make sufficient space between the isolating layer and the metal floor to be able to install the lower part of the frame. Furthermore there must be sufficient space between the kitchen unit and the frame of the screen, otherwise the frame of the screen will get stuck. In my case I had to adapt the roller blind by removing the cassette. I had to remove the screen door 3 times before it fitted well.