Air sealing and insulation are two different home performance improvements that work together to improve energy efficiency and indoor air quality. Air sealing involves sealing gaps and cracks in the building envelope, such as around doors, windows, and ductwork, to prevent air leaks and improve energy efficiency. Insulation, on the other hand, involves adding a layer of material, such as fiberglass, foam, or cellulose, to reduce heat transfer between the indoors and outdoors. Together, these improvements work to make homes more comfortable, energy-efficient, and healthy.