What type of insulation is commonly used in exterior walls?

When discussing insulation in exterior walls, it's important to recognize that each type of insulation mentioned serves a unique purpose and can be utilized effectively in various construction scenarios. Fiberglass insulation is widely preferred due to its excellent thermal performance, ease of installation, and non-combustibility. It comes in batts or loose-fill forms, making it versatile for different wall types.

Polystyrene, available in both expanded (EPS) and extruded (XPS) forms, is known for its high insulating value and moisture resistance, making it ideal for applications that require both insulation and protection from water damage. It is often used in insulating sheathing for exterior walls, which adds an extra layer of protection against the elements.

Cellulose insulation, made from recycled paper products, is blown into wall cavities and provides good thermal performance as well. It has a natural resistance to pests and is known for its environmentally friendly properties.

Because all these types of insulation serve different needs and can be chosen based on specific requirements such as climate, budget, and building codes, it is appropriate to classify them collectively as commonly used for exterior wall insulation. This comprehensive approach benefits builders and homeowners by providing various options to achieve energy efficiency and comfort.