Duct cleaning generally refers to the cleaning of various heating and cooling system components of forced air systems, including the supply and return air ducts and registers, grilles and diffusers, heat exchangers, heating and cooling coils, condensate drain pans (drip pans), fan motor and fan housing and the air handling unit housing.
If not properly installed, maintained and operated, these components may become contaminated with particles of dust, pollen or other debris. If moisture is present, the potential for microbiological growth (e.g., mould) is increased and spores from such growth may be released into the building’s living space. Some of these contaminants may cause allergic reactions or other symptoms in people if they are exposed to them.
Failure to clean an entire contaminated system can result in re-contamination, thus negating any potential benefits. NADCA recommends source removal method of duct cleaning. Source removal methods remove the dust, which is a food source for microbial contamination.
Some service providers may also suggest applying chemical sealants or other encapsulants to seal or cover the inside surfaces of the air ducts and equipment housings. They believe sealant will control mould growth or prevent the release of dirt particles or fibres from ducts. These practices have yet to be fully researched, and you should be fully informed before deciding to permit the use of encapsulates or sealants in your air ducts.
Encapsulants covering dust create a rough surface within the ductwork. This disrupts the air’s flow through the ductwork. Most encapsulants will break down with moisture, exposing the contaminant once again. Source removal is the preferred option.
Duct sanitisation involves applying chemical biocides, designed to kill microbiological contaminants, to the inside of the ductwork and other system components. The treatment is used in treating the walls, floors and ceilings of these air handling rooms and ducts, preventing the growth of bacteria and fungi for up to 12 months.