Should Biocides And Sealants Be Used In Ducts?

The air ducts that conduct cool and hot air from the HVAC to your rooms get infested with dirt and debris from time to time. They require cleaning. However, in some situations a simple cleaning process will not serve the purpose. This is mainly because the ducts have becomes breeding grounds of microbial beings. These need special treatment to terminate them. The contractor recommends proper source-removal practices for cleaning the duct work in your home. This is a good practice and gives the best results. However sometimes the contractors can recommend the use of sealants, chemicals, and biocides to address situations where source-removal alone may not be enough. Let us see the impacts of using these on your ducts –


An antimicrobial is an agent that kills microbial beings or terminates their growth. They are of various types. Such as antibiotics are used to kill bacteria, whereas antiphonals are targeted towards fungi. They can disinfect and sanitize HVAC units and the ducts as well. They are generally sprayed on the HVAC coils, blower or duct pipes. However, exposure to these can cause health hazards, especially if they are not used as per the instructions on the label.


This is another solution to keep the problem of mold or bacterial contamination of ducts at bay. Also called resurfacing the duct work, they are required if the sealant on your fiberglass duct board, or fiberboard, is wearing away. They are designed to extend the lifespan of the duct work and ensure that the HVAC system is functioning properly. Applying them is a purely technical task and needs a qualified professional. The use of encapsulates can eliminate odors, protect the system from rust and prevent moisture issues. It makes the interior surface of ducts smooth, thus increasing airflow. It also reduces the buildup of airborne contaminants in the ducts. However, little is known about the potential toxicity of these products.

Coil cleaners

Coil cleaners are used on the hard surfaces of the duct work and HVAC system. They are specially used on the coil to remove build ups. Coil cleaners are of two types the acid ones and alkaline ones. The former works faster and does not require heavy scrubbing. They are useful in case the coils have become very dirty.


If you have maintained your ducts meticulously, then a simple homemade solution of water, detergents and soaps can effectively clean the ducts and HVAC system. These will work when the buildup is minimal. These are easy to use and also cut down your cleaning costs.

If the contractors that you have hired are suggesting a use of chemical, then always check the Material Safety Data Sheet (MSDS) on the solution. This will ensure that he chemical is approved and recognized by EPA. If the contractor can't show you the MSDS, don't agree to the use of the chemical in your home.




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