Fiberglass is a type of silicate fiber primarily composed of glass that is used in a wide variety of applications, and is predominantly employed as a residential and commercial thermal insulator. As an insulator, it slows the spread of heat, cold and sound in structures, cars and aircraft while maintaining moisture resistance. Fiberglass absorbs sound waves and works as a non-conductive and radio frequency transparent. Fiberglass insulation allows design freedom and is highly cost effective.