When you think of air ducts, you typically think of sheet metal constructed tubes. However, many newer residential air duct systems are made of fiberglass duct boards. Some are even made of both materials, sheet metal on the outside and fiberglass interlinings on the inside.
Dating all the way back over 30 years, there has been an increase of flexible ducts that are made of plastic and other material on the inside. Over the years, due to the development of temperature control, reduced condensation, and energy conservation, people are using insulated duct material more and more.
Air ducts that have internal insulation offer acoustic noise control. Duct that are flexible are less expensive. They are manufactured solely for ducts or used as ducts themselves. They are tested with the guidelines standards of the Underwriters Laboratory which is the American Society of Testing and Material.
A large number of traditional air duct systems have been in operation for years while lacking the resistance of mold growth. Maintaining cleanliness for these generally works very well, however, there are arguments that porous insulation material such as fiberglass are more susceptible to microbial contaminants than sheet metal.
A substantial amount of dirt and moisture in the ventilation system may result in the same degree in contamination in bare sheet metal and internally lined duct system. Treating contamination in sheet metal duct is less taxing than other materials. Treating and cleaning with an EPA approved biocide is quite possible for sheet constructed ducts. On the other hand, cleaning ducts containing fiberglass liners is considered as inadequate when trying to remove mold and preventing regrowth. There is not an EPA standard biocide for treating such element as porous material. Air duct cleaning Hacienda Heights recommends replacing the entire fiberglass duct in the event of mold buildup.