Are you ever reluctant to open your windows on a nice day because you're afraid you'll let flies in? It sounds simple, but window screens are probably the way to go. Putting screens on your windows is one of the very best ways to keep flies and other insects out of your home.The University of Nebraska-Lincoln also recommends caulking your windows and covering entrances to the house from the outside. Make sure to do all of this during the spring and summer months before they decide to buzz in and lay a ton of eggs in and around your home! Adding window screens are also a great and inexpensive way to keep your home cool in the summer months, cutting down on your energy costs.