What is the primary function of air barriers in building construction?

The primary function of air barriers in building construction is to help control both heat and moisture flow, making the correct answer that reflects this is the one that mentions the dual role of these barriers. Air barriers serve to limit the movement of air between the inside and outside of a building, which is crucial for maintaining indoor air quality and energy efficiency. They prevent unwanted drafts and air leaks that can lead to temperature fluctuations, increased energy costs, and potential moisture issues.

In addition, by controlling the air movement, air barriers also play a key role in managing moisture. Moisture-laden air can condense within building assemblies, leading to mold growth and structural damage. An effective air barrier thus helps protect against these potential issues by regulating both heat and moisture flow within a building.

While it might seem that air barriers could only play a role in one aspect, they are designed to enhance the building's overall performance by managing both heat loss and moisture control effectively across various climates, thus proving their importance beyond just warm climates or a singular focus on either heat or moisture control.