High temperatures can cause a painted Door to blister and peel. If your front door has a glass storm door, in direct sunlight it can trap enough heat to melt the door Paint and cause unsightly paint failure. To prevent further damage of paint finish remove all loose and blistered paint my sanding to provide a smooth surface for repainting. Next apply 1 ct of exterior alkyd base primer-sealer, follow by 2 coats alkyd semi-gloss exterior enamel.[Avoid using latex or water base acrylic paints as these are more prone to heat damage.]
Another fix for this problem is simply using white or a lighter paint color choice for the front door. Lighter paint colors reflect sunlight caused heat better and allow for the paint to remain stable and last longer between paint jobs.