Which type of insulation is commonly used to improve energy efficiency in buildings?

The correct answer is comprehensive because all listed insulation types—fiberglass, cellulose, and spray foam—are effective in improving energy efficiency in buildings.

Fiberglass insulation is widely used due to its availability, cost-effectiveness, and proven ability to reduce heat transfer. It is made from fine strands of glass that trap air, providing excellent thermal resistance.

Cellulose insulation, made from recycled paper products, offers a sustainable option with good thermal performance. It is often treated with fire retardants and can be blown into wall cavities and attic spaces, effectively filling gaps and reducing air leaks.

Spray foam insulation creates an airtight seal when applied, expanding to fill cracks and gaps, which minimizes energy loss. It has a high R-value, indicating its effectiveness at preventing heat flow, and can contribute to significant energy savings.

Each type of insulation has its unique advantages and applications, making them appropriate choices for various building projects to enhance energy efficiency. Hence, all three types collectively contribute to improved energy efficiency, validating the selection of all of the above as the correct answer.