I have no idea why, neither windows nor doors have screens here in NZ. I was going to say they don't exist, but a quick check of Google shows you can now get this in high-end and custom doors for $$$. You can get magnetic overlays for windows, presumably ones with ferrous content in their frames (not a given). This in a country where gaps in window and door housing were put in deliberately for many years, or louvred windows that cannot close all the way, ostensibly for ventilation.