The term for air entering a building when outdoor air is warmer?

The term for air entering a building when outdoor air is warmer?

• A. Infiltration
• B. Exfiltration
• C. Conduction
• D. Convection

Answer: (A)

Air entering a building from outdoors is infiltration—the unplanned entry of outside air through cracks, gaps, and openings in the building envelope. It happens when pressure differences caused by wind or the stack effect pull outdoor air inside. When outdoor air is warmer than indoor, this inward air can raise indoor temperatures and increase cooling needs. This term is distinct from exfiltration, which is air leaving the building, and from conduction or convection, which describe heat transfer mechanisms rather than the direction of air movement.

Air entering a building from outdoors is infiltration—the unplanned entry of outside air through cracks, gaps, and openings in the building envelope. It happens when pressure differences caused by wind or the stack effect pull outdoor air inside. When outdoor air is warmer than indoor, this inward air can raise indoor temperatures and increase cooling needs. This term is distinct from exfiltration, which is air leaving the building, and from conduction or convection, which describe heat transfer mechanisms rather than the direction of air movement.