How is an air leakage rate higher than expected in a building typically addressed?

An air leakage rate that exceeds expected levels indicates that there are pathways through which conditioned air is escaping and unconditioned air is entering, which can lead to increased energy costs, discomfort, and reduced indoor air quality. Addressing this issue typically involves sealing gaps and improving insulation throughout the building.

Sealing gaps, such as those around windows, doors, electrical outlets, and in other areas where building materials meet, is critical because it directly reduces the amount of air that can flow in and out of the building. This process often includes caulking, weatherstripping, and using expanding foam for larger openings. Improving insulation complements this effort by reducing the thermal bridging that occurs in poorly insulated areas, which helps maintain a consistent indoor temperature and further mitigates air leakage.

The other options do not effectively mitigate air leakage: removing all windows would compromise the building envelope and create significant exposure to the elements; installing more ventilation systems could increase the introduction of outside air, potentially worsening the problem; and using single-pane glass does not provide an effective air seal or insulation compared to double or triple-pane windows, which help limit air movement. Therefore, sealing gaps and improving insulation are the most effective strategies for addressing higher than expected air leakage rates.