Which type of insulation is primarily used within the walls of homes?

Fiberglass insulation is widely used within the walls of homes due to its effective thermal resistance properties, cost-effectiveness, and versatility. It consists of fine glass fibers that trap air, thereby providing excellent insulation against heat transfer. Fiberglass batt insulation is particularly popular for wall applications because it is easy to install in standard stud spaces and is available in various thicknesses to accommodate different R-values, which measure insulation effectiveness.

Other types of insulation are indeed used in residential construction, but they serve different purposes. Foam board, for instance, is often employed for exterior insulation or in specific areas like basements rather than within standard wall cavities. Spray foam insulation provides superior air sealing and insulation values but is usually more expensive and is applied in a manner that can be less convenient for standard wall installation. Mineral wool is also a suitable insulator offering fire resistance and soundproofing qualities, but fiberglass remains the most common choice due to its widespread availability and proven performance in residential wall applications.