Air leaks affect insulation by

• A. Improving heat retention
• B. Bypassing insulation and carrying moisture
• C. Decreasing heat loss
• D. Only affecting cooling

Answer: (B)

Air leaks undermine insulation by creating pathways for air to move through the building envelope, bypassing the insulation material and carrying heat with it. Instead of heat having to travel through the insulation itself, air slips through gaps, reducing the effective resistance to heat flow and making the space feel drafty. The movement of that air can also transport moisture, which can condense in wall cavities, degrade insulation performance, and promote mold or wood damage. That combination—heat bypassing the insulation and moisture being carried by the air—explains why leaks weaken insulation so much. The other options imply that leaks improve retention, reduce heat loss, or only affect cooling, which isn’t accurate; leaks generally increase energy losses in both heating and cooling scenarios.