What is exfiltration?

Exfiltration refers to the process where air flows out of a building from the conditioned space, which is the area that has been heated or cooled for comfort. This movement typically occurs through unintentional leaks in the building envelope. Understanding exfiltration is crucial because it affects indoor air quality as well as energy efficiency.

When conditioned air escapes a residence, it can lead to increased energy costs as the heating or cooling system works harder to replace that lost air. It also can influence humidity levels and the entry of unconditioned air, which may carry pollutants or cause drafts. This concept underscores the importance of properly sealing a building to maintain energy efficiency and a comfortable indoor environment.