Moldy Air Conditioning Ducts – Do You Know What To Do?

Fungal and bacterial growth inside ductwork is a common problem, especially in high humidity areas. AC ductwork that is incorrectly installed can also cause mold growth issues. Over the years I have spoken to quite a few HVAC contractors, hygienists, and remediators and I’ve learned that mold in ductwork is a standard problem. It’s important to note that any issue in your home that will cause or worsen mold in your ductwork should be found and eliminated. Replacing or cleaning ducts while having an active mold problem in your home does not make sense, so always repair any areas causing water intrusion and remediate areas affected by the mold professionally before moving on to the ducts. *Note that in serious cases where people have been crippled by toxic mold they unable to stay in a remediated structure*

Below are a few pointers I have learned along the way. This is by no means legal or professional advice, it is shared for informational purposes only.

When dealing with ductwork issues consider the following:

– Were ducts installed properly? This is especially important if you are considering the purchase of a new home. In Florida and in GA, for example, I have heard numerous complaints of AC ductwork in an attic being installed directly on the truces which should not be the case. Ductwork should be elevated to avoid a mold growth problem. There is also an issue with lack of ventilation in homes built in the South East which can lead to mold issues.

– Depending on test results for mold in your home, ductwork can be cleaned if there is no toxic mold and or replaced completely if toxic mold is found. If you are not sure what to do about testing click here. 

– Ductwork replacement and or cleaning should be done by a licensed AirConditioning Contractor who is NADCA certified and preferably also certified in mold remediation, especially if you have mold in your ducts. You can also check if a company is licensed by finding your state’s Department of Licensing and Regulation office. For example, if you live in TX you would look up a business here to see if they are licensed. If you live in FL you would click here.
Looking up their rating on the website for the Better Business Bureau is also a good idea. There you will be able to read complaints filed against them and also see if they are an accredited business.

– If you are going to contract someone to clean your ductwork please keep in mind that they will clean ducts by using brushes, a vacuum, and negative air pressure. A responsible contractor will set up a workspace by covering the floor and any furniture and belongings in and around the areas where they will be working. They will also be careful to not cross-contaminate your space.
If you are chemically sensitive make sure you ask for a sample of all products being used to determine your tolerance. In my personal opinion, I do not recommend cleaning ducts if there is toxic mold. Cleaning can be very helpful however if ducts are dusty or in the case of new construction where dust from construction is inside of the ducts. If the ducts in my home were contaminated with toxic mold I would replace them and make sure that prior to making that investment I didn’t have a toxic mold issue in the rest of the home.

– Cleaning the ductwork is not enough, however. Make sure that your Air Handler unit, coils and all electrical components are taken apart and cleaned outside of your home. Cleaning the ductwork and not the rest of the HVAC components is a total waste of money and not recommended as you will just recirculate allergens in your home once your heating and or cooling is turned on.

– After cleaning fiberglass or fiberboard ducts it is imperative that the same ducts be sealed. The cleaning process will undoubtedly detach fiberglass particles and if ducts aren’t sealed these particles can be blown into the air once the heating and or cooling system is turned on. Breathing in fiberglass particles can lead to mesothelioma and other serious health issues. To seal ducts companies around the country I’ve interviewed use a product called IAQ8000. Similar products are available but I have yet to find one that is recommended for people who are chemically sensitive. After ducts are sealed some contractors will tell you that you can reenter the home within a few hours, I would recommend leaving for at least 3 to 5 days. I would also recommend running your AC and a good quality HEPA and VOC filter inside your home during the days you are away.

– Keeping a clean AC air filter for your home is super important. Changing your filter every 30 to 60 days is also very important. I can’t even begin to tell you the dozens of homes my husband saw last year that had massive fungal growth on the AC filter. We were searching for a new home and out of dozens of homes, only one had a somewhat clean HVAC system. Sadly this is a problem all around the country due to lack of education and information by both landlords and tenants. In most cases, people don’t service their AC units and they never change the filter. A dirty and moldy filter is a dead giveaway that the landlord and or business owner does not service and maintain the HVAC system or take care of the property as needed. To find your HVAC filter look for the return register and the air handler. The return register is usually a square or rectangular-shaped grille that is on the wall or on the ceiling. The air handler is the part of your HVAC system that is inside of your home, it is where the air is cooled. The air handler can be tucked away in a closet, attic, crawlspace, or basement.

– If fogging your attic or HVAC system is ever recommended please always check with a licensed mold remediator and an HVAC contractor as this can cause health issues and contribute to more mold growth down the line. As of today, fogging ductwork is not a practice that is recommended by NADCA and the EPA.  Fogging agents like one sold by have other uses that may be helpful and can be used for fogging rooms after mold remediation is completed. The fogging agents sold by US Enzyme are enzyme-based cleaners that may cause fewer reactions in chemically sensitive individuals which is a plus for those seeking less toxic solutions for cleaning. Their products are made for the DIY homeowner and for commercial use and can be used to wash things as well.

These are just a few tips, for now, please check back often as I will be updating this post periodically.

With Love
Chemical Free Gal

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