Various practices can be followed to mitigate mold issues in buildings, the most important of which is to reduce moisture levels that can facilitate mold growth. Properly functioning air conditioning (AC) units are essential to controlling levels of indoor airborne fungal spores. Air filtration reduces the number of spores available for germination, especially when a High Efficiency Particulate Air (HEPA) filter is used. A properly functioning AC unit also reduces the relative humidity in rooms. The United States Environmental Protection Agency (EPA) currently recommends that relative humidity be maintained below 60%, ideally between 30% to 50%, to inhibit mold growth. Considering that fungal growth requires cellulose, plant fiber, as a food source, using building materials that do not contain cellulose is an effective method of preventing fungal growth.