The exterior of your home is also called the "envelope" or shell. The insulation, outer walls, ceiling, doors, windows and floors all work together to control airflow in and out of your house, repel moisture and prevent heat from being lost or gained inside your home. The goal of air sealing and insulation is to improve the envelope to make a home more comfortable and energy efficient.  

Gaps and cracks allow air to leak in and out of your house, causing a loss of both energy and money. Older homes can have some of the worst air-leak problems. Installing weatherstripping, caulking windows and doorway seals, and adding insulation can help keep winter’s heat—and summer’s cooled air—inside your home where it belongs.

Best Practices for Air Sealing and Insulation