The presence of mold in an HVAC system is a common complaint. Mold is a sneaky little bugger. It can grow and proliferate and make building occupants sick without ever being seen. And the fastest way to spread mold through a building is through a forced-air HVAC system.
The reason this complaint is so common is that mold is always present in your buildings and your HVAC system to the extent that it is present in your building’s environment. There will be more mold in humid weather and less in dry weather. You will never get rid of it completely, but you can control it. All it needs to grow is moisture and food. Take those away and the mold goes away.
According to the U.S. EPA, you should routinely inspect your HVAC systems, not just for mold, but for moisture. Look at drain and condensate pans to make sure they are draining properly. If they are plugged, the moisture that accumulates will become a mold factory. Also make sure that all HVAC ducts and system components such as air handlers, blowers, plenums and the like are free of any moisture.
If, despite regularly inspecting your system, you are still getting complaints about it (mold starts to grow in as little as 48 hours), here are some tips you can share with your HVAC contractor for cleaning it up:
1.) Turn off your HVAC system.
2.) Everyone involved in this cleaning should wear at least an N-95 respirator
3.) Replace anything porous, such as filters or insulation that has become wet. Double-bag the waste using at 6-mil or thicker plastic bags.
4.) Use wet vacuums to clean out any standing water.
5.) Use an EPA registered disinfectant labeled for HVAC use to clean nonporous surfaces (Ductwork, coils, plenums, pans, etc) of mold, mildew and other dirt. BBJ MMR-II ready-to-use disinfectant and mold cleaner will kill and remove mold, mildew and odor-causing bacteria.
6.) As an added measure, isolate each section of ductwork you clean with bladders so the spores you stir up during cleaning don’t spread to other parts of the system or the building. Fog the area with an EPA registered disinfectant.
7.) Apply a mold and mildew inhibitor to all components of the HVAC systems. Again, this must be EPA registered and specifically labeled for use in HVAC systems to limit risks associated with using the wrong chemicals and cleaners in HVAC systems. Goodway’s CoilShine-BC is EPA registered for use in HVAC systems to control mold growth for up to 2 years.
8.) As a final step, HEPA vacuum anything that you cleaned up.
If you have mold, can it be cleaned safely?
If it is confirmed that you have a problem, the Environmental Protection Agency (EPA) suggests, “Do not run the HVAC system if you know or suspect that it is contaminated with mold – it could spread mold throughout the building.”
This is what the Center’s for Disease Control (CDC) advises if you have suspect that you have mold in your HVAC:
You may need to hire a professional to inspect your system. Any needed repairs or cleaning of vents and air ducts should be performed before restarting the system.
Throw away wet or water damaged filters.
Do not run your HVAC system if you know or think that it is contaminated with mold — it could spread mold throughout your home.
Turn off your HVAC system and cover vents and ducts during cleaning to prevent contaminating it.(3)
Of course, if it is the dead of winter in the cold states or high noon in the summer, it can be dangerous to not have heating or cooling running. With that said, you are going to have to get to work to handle this ASAP.
The first step is to determine if it can be cleaned properly and safely or if you have to replace the ducts in your home. If you are renting and there is no way to clean the system or replace it, then you will have to consider moving to a safe place.
In order to figure out the next step, you need to find out what materials your ducts are made of. This is crucial!
Many modern duct systems are made entirely of sheet metal. Others either have sheet metal with insulation on the exterior or with internal insulation and some are made entirely of fibrous glass insulation.
If you have a duct system that is made entirely of bare sheet metal or sheet metal with exterior insulation, you are most likely in luck. More often than not, they can be cleaned properly and safely if you hire a professional HVAC cleaner who has extensive experience with cleaning mold.
Please keep in mind that you do not want to hire amateurs to do this. Your health and life may be on the line here.
Sheet metal duct systems with an internal glass insulation or made entirely of insulation will have to be removed and replaced if they have water damage and or mold. There is no safe way around this fact and it can be very expensive. Here is what the EPA says, “If you have insulated air ducts and the insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced.”