Humidity control efforts in office buildings often focus on stopping the spread of mold and mildew, because these can lead to costly repairs and structural damage. However, the impact of humidity levels on occupant comfort should also be considered. Not only does proper humidity control improve indoor air quality, but evidence shows it increases worker productivity too.
The ideal humidity range for a building is between 40% and 60%. This is the range where most people feel comfortable. Elevated humidity levels can lead to health problems by encouraging the growth of bacteria and fungi or by aggravating allergies and respiratory infections. In fact, poor humidity control is a major contributor to sick building syndrome.
Beyond health issues, evidence has shown that humidity levels can have a direct impact on employee productivity. According to the World Green Building Council, a comprehensive body of research suggests that better indoor air quality can lead to productivity improvements of 8% to 11%.
Controlling humidity and moisture
Because elevated humidity levels contribute to poor indoor air quality, lower productivity and costly moisture problems, humidity control is a win-win situation.
Mold and mildew are frequently found on exterior-facing walls in corner rooms. Exposed corner rooms are often colder, making them a potential site for condensation. When mold or mildew is found in a corner room, it’s likely the relative humidity at the room’s surface is above 70%. This can happen even though the relative humidity is 30% and the temperature is 70°F in the middle of the room. If temperature is the dominating factor, increase cold surface temperatures with insulation or improved heat flow.
If the relative humidity is 50% and the temperature is 70°F in the middle of the room, the higher relative humidity at that temperature indicates the water vapor pressure is high and there’s a relatively large amount of moisture in the air. The high relative humidity at the surface is probably due to air that’s too moist. Humidity is the dominating factor, and control strategies should involve decreasing the moisture content of the indoor air.
There are several possible solutions for reducing relative humidity levels:
- Prevent hot, humid, outside air from contacting cold, indoor finishes.
- Eliminate cold spots by relocating ducts and diffusers.
- Make sure vapor barriers, facing sealants and insulation are properly installed and maintained.
- Increase the room temperature to avoid over-cooling.
By following these strategies, you can improve the comfort and productivity of your staff and reduce maintenance costs and structural damage to your building.