What is the effectiveness of air sealing compared to installing a vapor diffusion retarder?

Air sealing is fundamentally about preventing unwanted airflow through gaps and cracks in the building envelope, while a vapor diffusion retarder is designed to slow down moisture diffusion. When evaluating their effectiveness, air sealing is typically recognized for its significant impact on energy efficiency and moisture control within a home.

By sealing air leaks, you can drastically reduce heating and cooling costs, as well as improve comfort levels by minimizing drafts. Effective air sealing can lead to up to 100 times more effectiveness in controlling air movement and reducing energy loss compared to merely installing a vapor diffusion retarder, which focuses primarily on moisture control without addressing airflow.

While both techniques serve important roles in building science, air sealing addresses a broader scope of energy efficiency and comfort issues. On the other hand, a vapor diffusion retarder does not significantly enhance the protective qualities regarding airflow and energy efficiency, highlighting why effective air sealing stands out in this comparison.