Why do i get a build up of ice on my screen door every winter? it only happens on my front door to the house?

That is where the warm moist air inside your house meets the freezing cold. It may be that this is the door used most. Or it may indicate that you have a poor seal around your inside door. Be sure to use a door sweep and/or a draft snake. At night you may be able to feel where the cold is coming in. That may be where the warm moist air is going out as well. When the inside air hits the cold metal screen the water freezes.Why do i get a build up of ice on my screen door every winter? it only happens on my front door to the house?
The seal around your entry door is probably bad.