When it gets really cold outside, we have a piece of heavy duty clear plastic that we hang over our sliding glass door. I cut it to fit the door and put a border of masking tape across the top of the plastic. To the masking tape I have four small strips of self sticking Velcro. The match to the Velcro is on the woodwork of the door. It is white, same as the woodwork and is not noticeable. It has been there for several years now. When I want to take the plastic down, I just detach it and fold it up and put it under the hutch out of the way. Most of the time, I put it up at night and take it down during the day. Works really well for us and makes a big difference in heating the room. That door does get cold.