By Mike Blow, O3 Chemicals
According to the Centre for Disease Control (CDC), moulds can cause nasal stuffiness, throat irritation, coughing or wheezing, eye irritation, and in some cases skin irritation. This is applicable for both commercial and domestic settings.
Mould growing in an air conditioning (AC) unit is not necessarily more dangerous than mould growing elsewhere in a building, however, every time you turn on the AC, it’s spewing mould spores and bacteria into the air, and your lungs. This exposes yourself and any vulnerable room occupants to a raft of potentially serious, even deadly health problems. A mouldy air conditioner is a recipe for chronic illness.
Not all moulds are created equal. Mould is a microscopic organism, a fungus. There are good and bad moulds. For example, camembert or brie cheese relies on mould for its distinctive flavour and texture. And where would we be without the wonder-drug penicillin? It’s derived from a type of mould that scientist Alexander Fleming stumbled across.
Unfortunately, the types of mould you might discover lurking in an AC unit aren’t particularly friendly or useful ones. In fact, they’re much more likely to cause you harm than good.
Mould spores are the mechanism through which mould reproduces. When an AC unit is at rest, it’s the perfect petri dish for a wayward mould spore to grow on. Once comfortably at home in the AC, a mould spore will reproduce. Further spores will be released and become airborne. They will then spread throughout a building, landing on food, clothes, and occupants. From there they may be consumed, or the occupant would breathe them in.
If one has an allergic sensitivity to mould, its presence in an AC is likely to trigger a significant reaction. Likewise, if you have asthma or any other respiratory illness, mould is a risk factor that can ultimately put you in hospital.
Some moulds are also thought to be responsible for the production of mycotoxins, a leading contributor to serious and life-threatening illnesses such as pneumonia, particularly in children, the elderly and the immune-supressed.
Mould in the AC or HVAC system
Now everyone knows that mould can grow in a building AC and exposure to it can lead to sickness. Whether you have a single AC unit or a full ventilation system, hazardous mould can make itself a home and cause significant challenges to deal with. Many modern homes also have a full HVAC (heating, ventilation, and air conditioning) system, which makes it all the easier for mould to become a problem because once it infiltrates one system, it spreads through the ducts to everything else.
A stand-alone AC window unit can still grow mould and blow spores into the room the unit is located in. In this scenario, since the air conditioner isn’t connected to any ducts, the mould will not spread in the same way. You’ll only have one AC unit and one room to worry about. But if the home or building has central AC, the smallest bit of mould can end up spreading through to every connected space.
How does mould make one sick?
Mould visibly grows on a single surface, but it also spreads invisible, microscopic spores through the air, which can then be inhaled into the body. Once mould spores enter the lungs, they can lead to a myriad of issues, from small annoyances (coughing and sneezing) to major respiratory problems (pneumonia, bronchitis, asthma attacks, and more).
Many people will also have an allergic reaction upon contact with mould. It is an extremely common allergen, so unless you’re one of the lucky few who is not allergic, expect more responses. Symptoms of an allergic reaction to mould include hives, rashes, and trouble breathing caused by swelling of the throat. Usually, these allergic reactions are relatively minor, but in some cases, they can be fatal.
The worst forms of mould actually create mycotoxins, a toxic substance that leads to even further medical issues. The most prevalent mycotoxin producer is known as Stachybotrys chartarum, or more commonly, black mould. Exposure to black mould has been tied to tons of health problems, from depression to eye infections to lung bleeding. It’s not to be taken lightly.
Mould can grow virtually anywhere in a building and regardless of location, exposure can lead to these health problems. However, mould located in AC units spread spores out into the air throughout a building, which makes it especially dangerous and especially likely to cause the variety of sicknesses.
How can you tell if the AC has mould in it?
It’s not uncommon for building occupants to go a long time before finding out that their AC has been spreading harmful mould spores. An occupant could even be getting sick without even realise it.
Mould in an AC unit is usually discovered during the course of maintenance, such as when someone is replacing filters or cleaning dust and debris out. In these scenarios, the mould could be discovered by the building owner, or by a professional HVAC technician.
One particular way to keep an eye out for mould is through scent. If there’s a musty or stale smell whenever you turn on an AC unit, it may point toward mould being present somewhere. You may also want to physically look for mould if occupants experience any sicknesses or other symptoms that could be connected to mould. Look through the list of symptoms and problems discussed above for some examples of what to look out for.
If you suspect that the AC unit may contain mould, you should begin by checking whatever parts of the unit are visible or otherwise easy to access, including the evaporator coils and filter. However, take note that these parts being clean doesn’t necessarily mean that you’re free of mould. Ducts, ventilation shafts, and other less easily visible areas may hide mould too.
The best way to be absolutely sure about whether or not you have a mould problem is to hire a professional to run individual tests in the space. In addition to confirming whether the mould is a problem, experts can return to the property after any moulds removal to retest and help make sure that you’re in the clear. If you’re looking for a professional to help you test for mould in your house, try to find individuals or companies who follow standards such as those created by the American Conference of Governmental Industrial Hygienists or the American Industrial Hygiene Association.
How to get rid of mould in an AC systems
If you’re using a standalone AC unit and discover mould in it, the solution is relatively simple, if a little spendy: throw it out and buy a new one. Things are a bit more complicated if you have a central air system. Merely replacing the air conditioner in your central air system is not enough, as it’s entirely possible (and even likely) that mould has already spread through the HVAC ducts connected to the AC system by the time that mould has been discovered.
Your best bet with a central air system connected to HVAC is to contact a professional and let them remove the mould. Such a complicated job requires special tools in order to ensure that it’s done thoroughly and that the air conditioning and ventilation systems are not damaged.
The Environmental Protection Agency (EPA) recommends making sure that you choose an individual or professional who sticks with the NADCA (National Air Duct Cleaners Association) standards when finding someone to help you remove mould from a property’s AC unit(s). Do your research to find someone who complies with those standards and has a history of reliable, high-quality work.