Doors are one of the most common sources of high heating and cooling costs throughout the year due to untreated cracks and openings. Duck Brand 36 in. Aluminum Door Bottom Seals provide a simple solution to blocking drafts and preventing insects water dust and debris from invading your home. Designed to seal gaps between the door bottom and threshold this seal keeps cold air out in the winter and the cool air in during the summer months. Use together with other Duck Brand weatherization products to make your home more comfortable and energy efficient all year long.