Vent cleaning can be a risky business if not done properly. Air pollutants can cause allergic reactions, such as runny nose, sneezing, and wheezing in people with asthma. 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 the particle (e.g., dust) levels in the air ducts are actually reduced when cleaning is done. 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's 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, 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, the service provider 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 you should be fully informed before deciding to allow the use of biocides or chemical treatments in your 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 the 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 the situation 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 vent 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 vent 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 vents had been left alone. A careless or inadequately trained service provider can damage your vents 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, there is no evidence that a small amount of household dust or other particles in vents poses any health risk. The EPA does not recommend that vents be cleaned except when necessary because of continuing uncertainty about their benefits under most circumstances.
However, they do 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. Some research also suggests that cleaning dirty cooling coils, fans and heat exchangers can improve efficiency of heating and cooling systems. However there is little evidence to indicate that simply cleaning vents will increase efficiency of these systems. Whether you decide to clean your home's vents or not preventing water and dirt from entering them is still one of most effective ways to avoid contamination. If you decide to clean your heating and cooling system make sure service provider agrees to clean all components of system and is qualified do so.