What is the ideal indoor relative humidity level for comfort?

• A. 10% to 20%
• B. 30% to 50%
• C. 50% to 70%
• D. 70% to 80%

Answer: (B)

The ideal indoor relative humidity level for comfort typically ranges from 30% to 50%. This level is considered optimal because it balances moisture in the air, promoting a comfortable environment while minimizing problems such as mold growth, dust mites, and other allergens that thrive in higher humidity levels. When humidity is maintained within this range, it helps with maintaining the right temperature perception, making people feel comfortable without the air feeling too dry or too clammy.

Maintaining relative humidity levels within this range also supports the efficiency of heating and cooling systems, allowing them to operate effectively without overtaxing energy resources. This knowledge is critical for HVAC professionals to ensure that indoor environments are both comfortable and healthy for occupants.