Also known as Plexiglass, acrylic is used as a substitute for glass in window panes. While more expensive and less scratch-resistant than glass, acrylic is lighter and less prone to shattering.
Sold under trade names including Makrolon and Lexan, polycarbonate windows are up to 250 times stronger than glass and 30 times stronger than acrylic. Its greater strength justifies its higher cost.
Window frames made of polyvinyl chloride (PVC) plastic resist weathering, insulate well against heat and sound and are termite-proof. Since PVC has its color built into the material, it needs no painting.