Cleaning Air Ducts
The air duct cleaning profession is still in its infancy, so there’s no simple test to determine whether or not you should have your air ducts in your home or business cleaned.
Duct cleaning has never been shown to actually prevent health problems. There are no studies that conclusively demonstrate that the dust particle levels in homes increase because of dirty air ducts. This is because much of the dirt in air ducts adheres to duct surfaces and does not necessarily enter the living space. It is important to keep in mind that dirty air ducts are only one of many possible sources of particles that are present in homes. Pollutants that enter the home, both from outdoors and indoor activities such as cooking, cleaning, smoking, or just moving around can cause greater exposure to contaminants than dirty air ducts. Finally, there is no evidence that a light amount of household dust or other particulate mater in air ducts poses any risk to your health.
You should consider having the air ducts in your home cleaned if there is substantial visible mold growth inside of your ducts or on other components of your heating and cooling system.
Many sections of your heating and cooling system may not be accessible for a visible inspection, so ask the service provider to show you any mold they say exists.
You should be aware that although a substance may look like mold, a positive determination can be made only by an expert and may require laboratory analysis for final confirmation. For about $50, some microbiology laboratories will tell you whether a sample sent to them is mold or simply a substance that resembles it.
If you have insulated air ducts and the insulation gets wet or moldy, it cannot be effectively cleaned and should be removed and replaced. If the conditions causing the mold growth are not corrected, mold growth will recur.
You should certainly clean your air ducts if they are infested with vermin, such as rodents or insects. If your ducts are clogged with excessive amounts of dust and debris and/or particles are actually released into the home from your supply registers, then you know it’s time for a cleaning.
Some research suggests that cleaning heating and cooling system components (like cooling coils, fans, and heat exchangers) may improve the efficiency of your system. This will result in a longer system life, as well as some energy and maintenance cost savings. However, little evidence exists that cleaning only the ducts will improve the efficiency of the system.
You may consider having your air ducts cleaned simply because it seems logical that air ducts will get dirty over time. Provided that the cleaning is done properly, no evidence suggests that such cleaning would be detrimental. The EPA does not recommend that the air ducts be cleaned routinely, but only as needed. If a service provider or advertiser asserts that the EPA recommends routine duct cleaning or makes claims about its health benefits, you should inform the EPA.
If you do decide to have your air ducts cleaned, take the same consumer precautions you normally would by assessing the service provider's competence and reliability.
Air duct cleaning service providers may tell you that they need to apply chemical biocide to the inside of your ducts as a means to kill bacteria (germs) and fungi (mold) and prevent future biological growth. They may also propose the application of a "sealant" to prevent dust and dirt particles from being released into the air or to seal air leaks.
Make sure you fully understand the pros and cons of permitting application of chemical biocides or sealants. While the targeted use of chemical biocides and sealants may be appropriate under specific circumstances, research has not demonstrated their effectiveness in duct cleaning or their potential adverse health effects. No chemical biocides are currently registered with the EPA for use in internally-insulated air duct systems.
Whether or not you decide to have the air ducts in your home cleaned, preventing water and dirt from entering the system is the most effective way to prevent contamination.
Courtesy of the U.S. Environmental Protection Agency (EPA).
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