Expect to see a reduction in the need for dust removal. Expect to see a reduction in reactions to environmental allergies, such as dust, dust mites, pollen, and similar allergens, while you're inside the house. Expect less bacteria, dust, dust mites, and other debris to circulate throughout the house through the duct system. Once everything is out of the ducts, the technician will check and disinfect every corner of the system.
This will remove any remaining dust, allergens or bacteria. It will also create a healthier environment inside the ducts, which means that there will be no more mold growth and will improve air quality. You may consider cleaning air ducts simply because it seems logical that air ducts get dirty over time and should be cleaned from time to time. As long as cleaning is done properly, there is no evidence to suggest that such cleaning could be harmful. The EPA does not recommend that air ducts be cleaned routinely, but only when necessary.
However, the EPA recommends that if you have an oven, stove, or chimney that burns fuel, they be inspected to make sure they are working properly and serviced before each heating season to protect against carbon monoxide poisoning. This is because much of the dirt in the air ducts adheres to the duct surfaces and does not necessarily enter the living room. On the other hand, if a service provider doesn't follow proper duct cleaning procedures, duct cleaning can cause problems with indoor air. The EPA does not recommend that air ducts be cleaned, except when necessary, due to continuing uncertainty about the benefits of duct cleaning under most circumstances.
Providers of air duct cleaning services may tell you that they should apply a chemical biocide inside the ducts to kill bacteria (germs) and fungi (mold) and prevent their biological growth in the future. Whether or not you decide to clean your home's air ducts, preventing water and dirt from entering the system is the most effective way to prevent pollution (see How to Prevent Duct Contamination). While many of these products can legally be used inside uncoated ducts if all the instructions on the label are followed, some of the instructions on the label may not be suitable for use on ducts. Providers of air duct cleaning services can tell you that they need to apply chemical biocides inside ducts as a means to kill bacteria (germs) and fungi (mold) and prevent biological growth in the future.
Manufacturers of products marketed to coat and encapsulate duct surfaces state that these sealants prevent dust and dirt particles inside air ducts from being released into the air. This is because much of the dirt that can accumulate inside air ducts adheres to duct surfaces and does not necessarily enter the living space. Whether or not you decide to clean your home's air ducts, it's essential to commit to a good preventive maintenance program to minimize duct pollution. Duct cleaning methods vary, although industry associations that deal with air duct cleaning have established standards.
These products are specifically designed for use in ducts or as ducts themselves, and are tested in accordance with standards established by Underwriters Laboratories (UL), the American Society for Testing and Materials (ASTM) and the National Fire Protection Association (NFPA). If sufficient dirt and moisture are allowed to enter the duct system, there may be no significant difference in the speed or degree of microbial growth in internally lined or bare sheet metal ducts. Cleaning the air ducts may be considered simply because it seems logical that the air ducts become dirty over time and that they should be cleaned from time to time.
