What should indoor relative humidity be at or less than during summer months?

Indoor relative humidity should be at or less than 60% during the summer months to maintain comfort and prevent issues such as mold growth and condensation. High humidity levels can create an environment conducive to biological growth, including mold and dust mites, which can adversely affect indoor air quality and health. Additionally, excessive moisture can make cooling systems work harder, leading to increased energy costs and discomfort.

A relative humidity level of 60% serves as a balance, ensuring that spaces remain comfortable while minimizing potential problems associated with higher humidity levels. Keeping indoor humidity below this threshold is part of effective home performance and energy efficiency practices, which are crucial in maintaining a healthy indoor environment during the hotter seasons.