A storm door is an outer door installed to the outside of your pre-existing exterior door. Storm doors typically either have glass or screen inside of its frame that allows sunlight in. Storm doors help shield your exterior door from any outdoor elements that can cause serious damage, such as wind, ice, rain, and other outdoor debris. Storm doors are effective at keeping out insects, while still letting outdoor light inside. When deciding whether or not you need a storm door, first think about the location of your exterior door and the weather your area experiences. If your exterior door is under a deck or awning and experiences pretty mild weather, then you can probably do without an exterior door. If your exterior door, however, is not protected by any overhang and experiences harsh weather at times, then a storm door would be a great benefit to your home.