Whether you choose to clean your home's air ducts or not, the most effective way to prevent contamination is to prevent water and dirt from entering the system. If you decide to clean your heating and cooling system, it is essential to make sure that the service provider agrees to clean all components of the system and is qualified to do so. In addition, the service provider may suggest the application of chemical biocides, designed to remove microbiological contaminants, inside ducts and other components of the system. The Environmental Protection Agency (EPA) urges you to read this document in its entirety, as it provides important information on the subject.
Duct cleaning has never been proven to actually prevent health problems, nor do studies conclusively prove that particles (e.g., dust) are released into the air when the ducts are cleaned. This is because much of the dirt in the air ducts adheres to the surfaces of the ducts and does not necessarily enter the living space. It is important to note that dirty air ducts are just one of many possible sources of particulate matter that are present in homes. Pollutants that enter the home from both outdoor and indoor activities, such as cooking, cleaning, smoking, or just moving around, can cause greater exposure to pollutants than dirty air ducts.
In addition, there is no evidence that a small amount of household dust or other particles in air ducts poses any health risk. If any of the conditions identified above exist, it usually suggests one or more underlying causes. Before cleaning, reconditioning, or replacing the ducts, the cause or causes must be corrected, or else the problem is likely to reappear. Some research suggests that cleaning the components of the heating and cooling system (e.g., cooling coils, fans and heat exchangers) may improve system efficiency. However, there is little evidence that cleaning only the ducts improves system efficiency.
You may want to consider cleaning your air ducts simply because it seems logical that the air ducts will 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 is harmful. The EPA does not recommend that air ducts be cleaned routinely, but only when necessary. However, the EPA recommends that if you have a furnace, stove, or fireplace that burns fuel, they be inspected for proper functioning and maintained before each heating season to protect against carbon monoxide poisoning. If you decide to have your air ducts cleaned, take the same consumer precautions you would normally take when evaluating the competence and reliability of the service provider. Whether you decide to clean your home's air ducts or not, preventing water and dirt from entering the system is the most effective way to avoid contamination (see How to Prevent Duct Contamination).
If you decide to clean your heating and cooling system, it's important to make sure that the service provider agrees to clean all components of the system and is qualified to do so. In addition, they may propose applying chemical biocides designed to remove microbiological contaminants inside ducts and other components of the system. Some service providers may also suggest applying chemical treatments (sealants or other encapsulants) to encapsulate or cover inner surfaces of air ducts and equipment housings because they believe they will control mold growth or prevent release of dirt particles or fibers from ducts. These practices have not yet been thoroughly investigated and you should be fully informed before deciding whether or not to allow use of biocides or chemical treatments in your air ducts. They should only be applied if at all after system has been properly cleaned of all visible dust or debris. Knowledge about potential benefits and potential problems of air duct cleaning is limited.
Since conditions in every home are different, it's impossible to generalize about whether cleaning your home's air ducts would be beneficial or not. On other hand, if family members have unusual or unexplained symptoms or illnesses that you think might be related to your home environment, you should discuss situation with your doctor. The EPA has published following publications for guidance on how to identify potential indoor air quality problems and ways to prevent or fix them. You might consider cleaning your air ducts simply because it seems logical that they will get dirty over time and should be cleaned from time to time. While debate over value of regular duct cleaning continues, there is no evidence suggesting such cleaning is harmful provided it is done properly. On other hand, if service provider fails to follow proper duct cleaning procedures, duct cleaning can cause indoor air problems.
For example, inadequate vacuum collection system can release more dust, dirt and other contaminants than if ducts had been left alone. Careless or inadequately trained service provider can damage your ducts or your heating and cooling system which could increase your heating and air conditioning costs or force you to make difficult and expensive repairs or replacements. This is because much of dirt that can accumulate inside air ducts adheres to surfaces of ducts and does not necessarily enter living space. In addition there is no evidence that small amount of household dust or other particles in air ducts poses any health risk. The EPA does not recommend that air ducts be cleaned except when necessary because of continuing uncertainty about benefits of duct cleaning under most circumstances. However EPA recommends that if you have furnace stove or fireplace that burns fuel they be inspected for proper functioning and maintained.
