Duct cleaning can be a real hassle if not done properly. It involves removing dirt and debris from the air ducts and disposing of it in a safe manner. If the process is carried out by a professional, the air contaminants that have built up in the air ducts will be removed effectively. The science behind duct cleaning is still in its early stages, so it's difficult to make a general recommendation on whether or not air ducts should be cleaned.
The Environmental Protection Agency (EPA) recommends that you read this document thoroughly, as it contains important information on the subject. It has never been proven that duct cleaning can actually prevent health problems. Studies also don't conclusively show that particles (e.g., dust) are released into the living space when air ducts are cleaned. It's important to remember that dirty air ducts are just one of many possible sources of particulate matter in homes. Contaminants that enter the home from both outdoor and indoor activities, such as cooking, cleaning, smoking, or simply moving around, can cause greater exposure to contaminants than dirty air ducts. In addition, there is no evidence that a small amount of household dust or other particles in air ducts poses a health risk.
If any of the conditions identified above exist, it usually suggests one or more underlying causes. Before cleaning, modernizing, or replacing ducts, the cause or causes must be corrected, or else the problem is likely to recur. Some research suggests that cleaning the components of the heating and cooling system (e.g., coils, fans, heat exchangers) improves system efficiency. 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, they do recommend that if you have an oven, stove, or chimney that burns fuel, they should be inspected to make sure they are working properly and serviced before each heating season to protect them against carbon monoxide poisoning. If you decide to clean your air ducts, take the same consumer precautions you would normally take when evaluating the competence and reliability of the service provider. 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 contamination (see How to Prevent Duct Contamination). If you decide to clean your heating and cooling system, it's important to ensure that the service provider agrees to clean all components of the system and is qualified to do so. In addition, the service provider can propose the application of chemical biocides, designed to eliminate microbiological contaminants, inside the ducts and in other components of the system. Some service providers may also suggest the application of chemical treatments (sealants or other encapsulants) to encapsulate or cover the interior surfaces of air ducts and equipment housings, as they believe this will control mold growth or prevent the release of dirt particles or fibers through the ducts. These practices have not yet been thoroughly researched and you must be well informed before deciding to allow the use of biocidal products or chemical treatments in your home's air ducts.
They should only be applied after having properly cleaned the system of any visible dust or dirt. Knowledge about the potential benefits and potential problems of cleaning air ducts is limited. Since every home's conditions 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 your family members have unusual or unexplained symptoms or illnesses that you think might be related to your home environment, you should discuss this with your doctor. The EPA has published several publications as a guide to identifying potential indoor air quality problems and ways to prevent or solve them. You may consider cleaning your air ducts simply because it seems logical that they get dirty over time and should be cleaned from time to time. While there is still debate over how useful regular duct cleaning is, there is no evidence to suggest that such cleaning is harmful as long as it is done properly.
On the other hand, if a service provider doesn't follow proper procedures for duct cleaning it can cause indoor air problems. For example, an inadequate vacuum collection system can release more dust, dirt and other contaminants than if it had left them alone. A careless or inadequately trained service provider can damage your heating and cooling system which could increase heating and cooling costs or require difficult and costly repairs or replacements. This is because much of the dirt that accumulates inside air ducts adheres to their surfaces and does not necessarily enter your living space. In addition, there is no evidence that a small amount of household dust or other particles in air ducts poses a risk to health. The EPA does not recommend that air ducts be cleaned except when necessary due to continuing uncertainty about their benefits under most circumstances. However they do recommend that if you have an oven stove or chimney that burns fuel they should be inspected before each heating season for carbon monoxide poisoning. Some research also suggests that cleaning dirty cooling coils fans and heat exchangers can improve efficiency of heating and cooling systems but there is little evidence indicating simply cleaning your system will increase efficiency. If you think that cleaning your ducts may help improve your home's indoor environment then it's important you take consumer precautions when evaluating competence and reliability of service providers.
It's also important they agree to clean all components of your system before applying any biocidal products or chemical treatments.