Which of the following is listed as a moisture source?

• A. Window cleaning
• B. Drying clothes
• C. Light fixtures
• D. Paint

Answer: (B)

Understanding indoor moisture sources is about recognizing activities and materials that release water vapor into the air. Drying clothes is a genuine moisture source because wet fabrics emit water vapor as they dry, raising the humidity inside a space and increasing the risk of condensation or mold if there isn’t adequate ventilation or proper humidity control. The other options don’t contribute significant, ongoing moisture to indoor air: window cleaning involves water briefly and it dries quickly without lasting humidity; light fixtures don’t produce moisture themselves; paint, once cured, doesn’t continue to add moisture to the air in a meaningful way.