To insulate your entry door, you want to add weather stripping around your door to limit excess airflow. Certain types of doors include natural insulation, while others don’t. For example, wood doors expand or shrink as the temperature fluctuates, so weather stripping wooden doors is more difficult. However, fiberglass exterior doors can insulate your home more efficiently because they contain foam. Window World of Colorado entry doors are installed with weatherstripping seals already in place.