Which type of insulation is most commonly used in walls?

Fiberglass batts are the most commonly used insulation in walls primarily due to their balance of effectiveness, cost, and ease of installation. They are made of fine glass fibers that trap air, providing excellent thermal resistance (R-value), which is essential for energy efficiency in buildings. Their availability in different thicknesses and widths allows them to fit standard wall cavities, making the installation process straightforward for builders and contractors.

Additionally, fiberglass batts are lightweight, which simplifies handling and reduces labor costs during installation. They can be easily cut and shaped to fit around obstructions, and they do not settle over time, maintaining their insulating integrity. Furthermore, fiberglass is non-combustible and resists moisture, which helps prevent mold growth, making it a practical choice for many construction applications.

While other insulation types, like cellulose or mineral wool, also provide good thermal performance and some specific benefits, fiberglass batts remain the preferred choice for wall insulation in typical residential and commercial projects due to their demonstrated versatility and reliability in maintaining energy efficiency.