As the eyes of our houses, we hope windows are secure and beautiful. When buying windows, the first thing comes to your mind is material. Windows are made of frame and sash. Sash is usually made of glass while window frame materials could be vinyl, fiberglass and wood, etc. There are some elements your need to consider before making decisions: security, durability, cost, aesthetics, etc. What are their differences? Which is the most suitable choice for windows in a long term?