Through what process does air enter a house?

Air enters a house primarily through the process of infiltration, which refers to the unintentional or passive movement of outside air into a building, typically through cracks, gaps, or openings in walls, windows, and doors. This is a natural phenomenon that occurs due to differences in pressure inside and outside the home, often influenced by temperature variations.

Infiltration is important for ventilation as it helps to bring fresh air into indoor spaces, thereby contributing to air quality and comfort. It can also play a significant role in heat loss during colder months and heat gain during warmer months, making it a key factor in energy efficiency.

The other terms listed, such as exfiltration, refer to the process of air leaving a building, while filtration pertains to the cleaning of air by removing particulates and pollutants, and quality control generally relates to standards and practices in various processes rather than the entry of air into a building. Thus, infiltration is the correct answer as it specifically denotes the entry of air into a house.