What is the ideal relative humidity range for a conditioned space?

What is the ideal relative humidity range for a conditioned space?

• A. 40% - 60%
• B. 20% - 40%
• C. 60% - 80%
• D. 30% - 50%

Answer: (A)

Maintaining a moderate relative humidity in a conditioned space helps keep occupants comfortable while reducing moisture-related problems. The ideal range is 40% to 60% because it balances comfort with controls on condensation and mold growth. If humidity drops below 40%, the air can feel dry, causing skin and throat irritation and increased static. If humidity climbs above 60%, surfaces can stay damp, leading to condensation, musty odors, and a higher risk of mold and dust mites. While some environments tolerate narrower bands like 30-50%, the 40-60% range serves as a practical, widely applicable target for most buildings and climates to support both comfort and indoor air quality.

Maintaining a moderate relative humidity in a conditioned space helps keep occupants comfortable while reducing moisture-related problems. The ideal range is 40% to 60% because it balances comfort with controls on condensation and mold growth. If humidity drops below 40%, the air can feel dry, causing skin and throat irritation and increased static. If humidity climbs above 60%, surfaces can stay damp, leading to condensation, musty odors, and a higher risk of mold and dust mites. While some environments tolerate narrower bands like 30-50%, the 40-60% range serves as a practical, widely applicable target for most buildings and climates to support both comfort and indoor air quality.