MOLD IN THE AIR DUCTS?

How to remove mold in the ducts is a common question that is asked. Can Vacu-man remove mold from the air duct system? Keep in mind that many air duct systems are treated with an oil-based covering that allows them to be protected from having anything stick to the surface of the inside. In addition, this also allows for any dust and debris to be easily removed.

That said, over time, air duct systems can get damaged, with the systems being scratched, thus allowing for the building up of debris, and should moisture occur where the air ducts are not treated, it could lead to rusting. Over time, moisture builds up on any dust, hair, and particles in the air duct system, or the furnace becomes a food source for mold.   That mold spore growth would then be circulated through the home air environment.  

WHERE DOES IT RUST?

The furnace system is most likely where rust could occur (over many years) and where moisture can accumulate, thereby creating mold build-up over time. This can be created on the A-coil, just above the heat exchange, or sometimes within the blower fan casing. It is a rare situation where mold buildup can occur.  This is rare primarily because air is flowing through your ventilation system, thereby causing any wetness or moisture to dry out.   

During the summer and warmer seasons, setting your air conditioner to a very low degree can create condensation and moisture. We recommend that you keep the airflow always moving through your HVAC system by keeping the blower fan on at all times. Not only will the airflow assist with keeping it cool, but it is also more energy efficient to keep the blower fan on versus the electricity it takes to fire it up and turn it off every time the AC kicks in.

Is Mold in Air Ducts a Health Risk?

For most healthy people, brief exposure to mold spores from ductwork isn’t a serious issue — everyone breathes in mold spores regularly without getting sick. That said, according to the CDC, mold exposure can trigger allergic reactions, worsen asthma, and cause respiratory irritation, and the risk is meaningfully higher for people with asthma, existing lung conditions, or weakened immune systems.

What about Aspergillus specifically? Aspergillus is a large genus with more than 250 species, and it’s one of the more common molds found in HVAC systems because — unlike many molds — some species can tolerate lower moisture levels, including dust buildup inside ductwork. The CDC identifies roughly 40 Aspergillus species as capable of causing infection in humans, most notably A. fumigatus. For the average healthy person, Aspergillus exposure typically causes nothing more than mild allergy-type symptoms, if anything at all. The real risk is concentrated in immunocompromised individuals and people with asthma or chronic lung disease, for whom it’s worth being more cautious and addressing any suspected mold promptly.

Should You Clean Mold From Air Ducts Yourself?

If you suspect mold in your ductwork, this isn’t a DIY project. Disturbing mold — scrubbing it, vacuuming it with a standard household vacuum, or spraying chemicals directly into the duct system — can release more spores into the air rather than remove them, spreading the problem to more of your home. Vacu-Man does not recommend spraying chemicals into duct systems, consistent with our approach to duct fogging generally: source removal by a trained professional, not chemical treatment, is the right first step. If you see visible mold, smell a persistent musty odor, or notice symptoms that improve when you leave the house, it’s worth having your system professionally inspected rather than attempting to address it yourself.

KEEP YOUR BLOWER FAN ON

Remember, it doesn’t hurt to have the blower fan running at all times, as it keeps the air circulating and any moisture that is in the air duct system can be evaporated.   Furnaces can build up water moisture, but that could be for other reasons.  We’ve outlined this in more detail with reference to water in the furnace.  Air duct system mold can occur, and to properly remove and ensure that it is cleaned on a regular basis, it is probably a good idea to have your air duct systems cleaned every 3 to 5 years.

Can Mold Grow in Air Ducts?

Yes, but it’s less common than many homeowners assume. Mold needs moisture, warmth, and a food source (dust, hair, and debris) to grow, and most air duct systems don’t hold onto moisture long enough for mold to take hold — air moving through the system typically dries things out. When mold does grow, it’s usually concentrated in specific spots: the A-coil, just above the heat exchanger, or inside the blower fan casing, where condensation is most likely to linger.

This will limit the amount of hair, dust, and debris that can get into your air duct system and your furnace, from being able to grow mold throughout the air system.

Vacu-Man highly recommends not spraying any chemicals into the air duct system.  Chlorine, which is highly effective at killing mold and preventing mold from happening, can cause more damage due to the fact that it circulates in the air at your home or office. This is not a recommended situation for what you should do. If you do have your air duct systems and air handler with mold… cleaning it may not be the solution. You may need to replace the air ducts, and further, if you do have mold in the furnace, you will want to speak with a service technician to assist in properly removing and replacing parts. 

MAINTAIN YOUR FURNACE AND AIR DUCT SYSTEM.

Proper maintenance of cleaning your furnace and air duct system will help prevent those situations that can lead to mold. Keeping your indoor air quality clean will limit the amount of allergic reactions and health issues that could occur. Make sure you hire an air duct cleaning service that cleans the air vents, the air conditioning, and your entire HVAC system, including evaporator coils, to ensure that any dust and debris buildup that can create a mold situation due to the excess moisture does not happen.

Want to learn more about mold? You can visit the EPA website on mold and control.

If you have any other questions or concerns, feel free to give us a call or send us a request for a quote, and we can understand specifically what concerns you have that Vacu-Man could assist with. Vacu-Man serves the Burlington, Oakville, Hamilton, Milton, and St. Catherine’s area.