Window screens are thin mesh barriers placed in window frames to keep insects and debris out while allowing fresh air to flow into a building. They are typically made from materials like fiberglass or aluminum and can be easily removed for cleaning or replacement. Screens come in various sizes to fit different window types and can be fixed or retractable. In addition to keeping bugs out, window screens can also help improve energy efficiency by reducing the amount of direct sunlight entering a home. This can help maintain a comfortable indoor temperature and protect furniture from fading due to UV exposure.