Which of the following is a major area for potential air leakage?

The selection of walls to fenestrations as a major area for potential air leakage is a critical consideration in building performance and energy efficiency. Fenestrations, such as windows and doors, are the points in walls where openings are created for natural light and ventilation. These openings can often present vulnerabilities if not properly sealed and integrated into the wall system.

Air leakage typically occurs around the frames of windows and doors due to inadequate sealing, poor installation practices, or the natural deterioration of materials over time. This can lead to significant energy loss, moisture intrusion, and a decrease in overall building comfort.

In contrast, while other areas like roofs to HVAC systems, floors to ceilings, and kitchens to bathrooms can also experience air leakage issues, they are generally less significant in terms of cumulative impact on a building's airtightness than the connections between walls and fenestrations. Ensuring proper sealing, flashing, and insulation around these key transitions is essential for maintaining an effective air barrier in a structure.