Mold In HVAC Systems


Mold in HVAC (heating, ventilation and air conditioning) systems can lead to serious health problems. Every time the furnace or air conditioner is turned on, hundreds of thousands of microscopic mold spores blow out of the air ducts and circulate through the air, where they are easily inhaled. Mold in duct work can lead to numerous health problems, including coughing, sneezing, wheezing, shortness of breath, sore throats, headaches, asthma attacks, bronchitis and pneumonia.

How Do You Know if There is Mold in HVAC Systems?

You should suspect mold in your HVAC system if you smell a musty odor in your home, especially if you smell it in more than one room or if it’s particularly noticeable when your furnace or air conditioner is running, but you don’t see mold anywhere. You should also consider the possibility of mold in your HVAC system if you find mold in several different rooms, since mold spreads easily through duct work.

The only way to know for sure if there is mold in your HVAC system, though, is to have your system tested for the presence of mold. Follow this link for a list of professionals in your area that can test your system for mold.

How Do You Remove Mold in Duct Work?

There are a number of techniques used to remove mold from duct work. Manual or mechanical brushes can be used to loosen mold growing in the air ducts. Blowguns, air skippers or air whips can be used to drive mold and other debris from the ducts into collection devices. Vacuums with HEPA filters are also used to remove mold from duct work. Chemical biocides may be used to kill any mold remaining in the HVAC system. Negative pressure is often set up in the work area to prevent mold spores from drifting to other areas of the home. Special techniques and equipment must be used if duct work is made of fiber glass duct board or insulated with fiber glass duct liner, in order to prevent damage to the ducts. 

Mold in Heating System

The Environmental Protection Agency recommends hiring a professional to remove mold from air ducts. That’s because special equipment is needed that the average homeowner doesn’t have lying around the garage, because it’s difficult to access all parts of the HVAC system, because duct work can be damaged if it’s not cleaned properly, and because if any mold is missed it can quickly spread throughout the system and that can lead to serious health problems for those living in the home. While a homeowner with basic handyman skills can successfully tackle many mold removal jobs, we recommend against trying to remove mold from your duct work unless you have professional training in the field.

Finding a Professional to Help With Mold in Duct Work

If you’ve got mold in your HVAC system, you need a professional to take care of it and make your home safe for you and your family. Look for a professional that complies with the standards established by the National Air Duct Cleaners Association. If your duct work is made of fiber glass duct board or insulated with fiber glass duct liner, look for a professional that also complies with the standards established by the North American Insulation Manufacturers Association. Many professionals will come to your home for a free consultation, inspect your duct work and any other areas of mold, and provide a written estimate detailing the work that needs to be done and the cost. Follow this link for a list of qualified professionals that can remove mold in HVAC systems in your area.


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