Which device is specifically used to control indoor humidity?

• A. Dehumidifier
• B. Exhaust ventilation
• C. Balanced ventilation
• D. HVAC fan

Answer: (A)

Controlling indoor humidity means actively removing excess moisture from the air. A dehumidifier is designed for this task: it pulls moist air over a cooled surface, condenses the water out, and returns drier air to the space, lowering the relative humidity to a comfortable target. This direct moisture removal helps prevent problems like condensation, mold, and musty smells. The other options serve different purposes—exhaust ventilation mainly exchanges indoor air with outdoor air and can affect humidity indirectly; balanced ventilation focuses on air quality and energy recovery; and an HVAC fan simply circulates air without reducing moisture. So for actively managing humidity levels, a dehumidifier is the best choice.