What does air infiltration refer to?

Air infiltration specifically refers to the unwanted movement of air into or out of a building through components that are not intended to facilitate airflow, such as walls, ceilings, floors, and even small cracks and openings. This process can lead to significant energy loss and reduced indoor air quality, as it brings in unconditioned air from outside that can affect heating and cooling efficiency. The primary concern with air infiltration is that it is typically unregulated and may introduce various pollutants or allergens into the indoor environment, which can be detrimental to occupant comfort and health.

In contrast, controlled air exchange in ventilation is a deliberate process aimed at providing fresh air to a building while removing stale air, leading to healthier indoor environments. Air filtering inside the building focuses on purifying the air to improve indoor air quality, typically via the HVAC system. Absorption of air by insulation is not a standard term in this context, as insulation is designed to resist airflow and thermal transfer rather than absorb air. Thus, identifying air infiltration as unwanted air movement is crucial for understanding building performance and energy efficiency.