What is the term for air leakage leaving a building?

What is the term for air leakage leaving a building?

• A. Draft
• B. Exfiltration
• C. Ventilation
• D. Infiltration

Answer: (B)

Air movement across the building envelope is described as infiltration when air enters and exfiltration when it leaves. The term for air leakage leaving a building is exfiltration, because it specifically refers to conditioned air escaping from the indoors to the outside. Ventilation is the intentional or designed exchange of indoor air with outdoor air to control indoor air quality, not just leakage. A draft is a noticeable flow of air, often caused by leaks or pressure differences, but it’s not the technical term for the leakage itself. Infiltration would be air entering the building, not leaving.

Air movement across the building envelope is described as infiltration when air enters and exfiltration when it leaves. The term for air leakage leaving a building is exfiltration, because it specifically refers to conditioned air escaping from the indoors to the outside. Ventilation is the intentional or designed exchange of indoor air with outdoor air to control indoor air quality, not just leakage. A draft is a noticeable flow of air, often caused by leaks or pressure differences, but it’s not the technical term for the leakage itself. Infiltration would be air entering the building, not leaving.