What Temperature and Humidity Combinations Generate Mold?

Mold is a common problem in areas prone to high humidity, heat and moisture. Basements and other sub-level areas generally are the most common where mold problems are discovered. One way to prevent the growth and spread of mold is to keep these areas well-ventilated. This helps moderate moisture in the air as well as refresh stagnant air. Listed here are general temperature and humidity guidelines that contribute to the growth and spread of mold.

Humidity

• Humidity is of the most important factors that causes mold to grow. Mold has the capacity to grow when the humidity reading is as low as 10 percent to 14 percent. The mold growth will occur slowly. Humidity levels that facilitate mold growth generally exceed 60 percent. The potential for mold growth expands when the air is stagnant.

Dew Point

• Temperature works in correlation with humidity to generate an environment for mold growth. When air temperature increases then decreases, evaporation is released creates a dew point temperature. This moisture often is seen collecting on windows and, if left alone, will lead to mold growth. Dew point temperature most often occurs within a range of 70 degrees to 90 degrees. One example of a combination of temperature and humidity that will lead to a dew point temperature ripe for mold growth is 75 degrees with 20 percent relative humidity.

Materials

• In addition to temperature and humidity readings conducive to mold, fungus prefers to grow on organic and building materials, such as carpets, wood, books or drywall. The combination of temperature, humidity and material determines how quickly mold grows. Areas with organic materials routinely exposed to temperatures of 70 degrees to 90 degrees, with a minimum humidity level of 10 percent, often have issues with mold. Steps to eliminate these conditions include improving ventilation, installing a dehumidifier and removing the problematic materials.