A kit, door and method of installing an adjustable horizontal adapter bar for a storm, security, screen or other door to a building involves adjustment of a bar for a bottom or a top edge of a door to get a better fit than a standard door. Adjustable bars may comprise multiple telescoping parts, adjustable width vertical bars and fasteners for coupling the adjustable bar to a door. A kit may further comprise a threshold plate and a bug sweep for further resisting entry of bugs small animals and debris to create a better seal.