When it comes to cleaning air ducts, knowledge is still in its early stages, so it's difficult to make a general recommendation. The Environmental Protection Agency (EPA) urges people to read all the available information on the subject before making a decision. While duct cleaning has never been proven to prevent health problems, much of the dirt in the air ducts adheres to the surfaces of the ducts and does not necessarily enter the living space. It's important to note that dirty air ducts are just one of many possible sources of particulate matter present in homes.
Pollutants from both outdoor and indoor activities, such as cooking, cleaning, smoking, or just moving, 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. 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., coils, fans, and heat exchangers) may improve system efficiency.
However, there is little evidence that cleaning only the ducts improves system efficiency. People may want to consider cleaning their air ducts simply because it seems logical that they 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, they recommend 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 the application of chemical biocides designed to remove microbiological contaminants inside ducts and in other components of the system.
Some service providers may also suggest applying chemical treatments (sealants or other encapsulants) to encapsulate or cover the inner surfaces of air ducts and equipment housings because they believe they will control mold growth or prevent the release of dirt particles or fibers from the ducts. These practices have not yet been thoroughly investigated and people should be fully informed before deciding to allow the use of biocides or chemical treatments in their air ducts. They should only be applied, if at all, after the system has been properly cleaned of all visible dust or debris. Knowledge about the 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 the 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 it with your doctor.
The EPA has published several 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 there is still debate over whether regular duct cleaning is beneficial or not, there is no evidence to suggest that such cleaning is harmful when done properly. On the other hand, if a service provider fails to follow proper duct cleaning procedures, it can cause indoor air problems. For example, an inadequate vacuum collection system can release more dust, dirt, and other contaminants than if the ducts had been left alone. A 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. In addition, some research suggests that cleaning dirty cooling coils, fans, and heat exchangers can improve the efficiency of heating and cooling systems.
However, there is little evidence to indicate that simply cleaning the duct system will increase its efficiency. If you think duct cleaning might be a good idea for your home but are unsure about it, talk to a professional. The company that services your heating and cooling system should be able to provide advice on whether it would be beneficial for your particular situation.
