What does exfiltration describe?

Exfiltration refers to the unintentional flow of air out of a building, which typically occurs due to differences in pressure between the inside of the home and the outside environment. This can happen through various pathways, including cracks, gaps, or holes in the building envelope. Understanding exfiltration is crucial for assessing a home's energy performance and indoor air quality because it can lead to a loss of conditioned air, resulting in increased energy costs and decreased comfort.

In contrast, the other options describe different scenarios or processes. Intentional airflow into a home characterizes situations where air is deliberately drawn inside, which directly contrasts the concept of exfiltration. Controlled exhaust refers to a methodical process of removing indoor air, often regulated by mechanical ventilation systems, rather than the random and uncontrolled leakage represented by exfiltration. Similarly, heat escaping through windows relates to thermal loss but does not specifically address air movement and leakage, which is the focus of the term "exfiltration."