A magnetic weatherstrip is designed to stick to a metal door. This does not necessarily mean that you have to only use it on metal doors. You could also potentially install a magnetic weatherstrip on the inside of the door frame if you have a metal frame. The weatherstrip can be attached to the door frame, and it will provide extra insulation around the edge of the door so that air can not get in or out. These products are very easy to install as long as you have some type of metal to attach them to.