What does "air barrier retrofit" refer to?

The term "air barrier retrofit" specifically refers to the addition of an air barrier to an existing building. This process is significant in improving the building's energy performance by minimizing air leakage, which can compromise comfort and increase energy costs. In many cases, existing buildings were not constructed with adequate air barriers, leading to drafts and inefficiencies. By retrofitting an air barrier, these issues can be addressed, ensuring better control over air movement and enhancing the overall performance of the building envelope.

While the other options might relate to air barriers in different contexts, they do not accurately capture the essence of "retrofit" as it pertains to introducing new air barrier materials or systems into an existing structure. For instance, removing old barriers does not enhance performance if there's no replacement, and repairing existing barriers focuses on maintenance, rather than improvement through the addition of new barriers. Maintaining ventilation systems is important for indoor air quality but is separate from the concept of retrofitting air barriers aimed at controlling air leakage.