Glass Wool

Glass wool is a fibrous insulation material manufactured from molten glass spun into fine fibers, widely used for acoustic absorption and thermal insulation. It provides high sound absorption (NRC 0.80–1.00) through viscous losses as sound passes through the fiber matrix. Glass wool is lighter than mineral wool (typically 10–48 kg/m³) and is commonly used in ceiling tiles, wall cavity insulation, and HVAC duct lining. Its acoustic performance is governed by thickness, density, and airflow resistivity, with optimal values for absorption typically between 5,000 and 20,000 Pa·s/m². Glass wool products are tested per ISO 354 for absorption and rated using NRC, SAA, or αw. In sound insulation applications, glass wool fills stud wall cavities to reduce cavity resonance. It is widely available globally from manufacturers such as Isover (Saint-Gobain), Knauf Insulation, and Owens Corning.