Fiber glass duct liners and duct board have been incorrectly blamed for contributing to mold growth in high humidity and high temperature conditions. The fact is that fiber glass is inherently resistant to mold growth. Stringent testing in accordance with UL and ASTM standards confirms that fiber glass duct liners and duct board do not support mold growth.

In instances where mold growth has been detected on the interior surfaces of the duct system, the cause has been an accumulation of dust and dirt combined with the presence of water. Under these conditions, mold can grow on any interior surface.