It’s the height of summer, and all the lovely cool air coming from your air conditioner is being ruined by a musty smell, or a sudden rise in allergies!
The bad news? You might have mould in your air conditioner system. The good news? We’ve put together a handy step-by-step guide on how to clean mould from your air conditioner vents.
But first, let’s take a look at what causes the problem.
What causes mould in air conditioning vents?
Air conditioners work by alternately evaporating and condensing a liquid refrigerator, which in turn heats and cools the air passing through the system. Using interior fans, cool air is pushed back into the room, while warm air is sent outside.
The problem is that this process involves a lot of moisture moving around the system, and there’s nothing mould and mildew love more than dark, damp places. And on hot days, when the system is turned off, residual moisture in the air conditioner vents provides the perfect spot for mould spores to set up home.
When the system is turned on, those spores will head out alongside that much needed cool air, ready to be breathed in by anyone in the room, or to take up a new home in another damp corner.
You may also find mould in your air conditioner vents if your unit is oversized for the space it occupies, if you keep the temperature too low, or if you have leaks in the system.
What are the signs of mould inside air conditioner vents?
One of the earliest signs of mould in an air conditioning unit is a musty smell when the system is in use. You might also see an increase in allergy symptoms, such as itchy eyes, a runny nose, or sneezing.
Mould isn’t always visible, but when it is, it takes on a variety of colours and textures. A specific type known as black mould can show itself as black spots. Black mould can be very dangerous, and a specialist cleaner is recommended to tackle it.
Why is it important to clean mould?
While a bad smell and a bit of coughing and sneezing might not sound like the worst thing in the world, it’s very important to clean mould from air conditioner vents.
Those early symptoms can get worse over time, and other health issues such as fatigue, headaches, wheezing and shortness of breath can occur. Both healthy people and those with pre-existing conditions are at risk, breathing in the cool air as it is fanned into the room.
How to clean mould from air conditioner vents
Depending on the type of unit you have, it might be best to call in the professionals, but if you’re looking to tackle the job yourself, here’s our step-by-step guide to cleaning your vents:
1. Put on the appropriate protective equipment.
Gloves, safety glasses, and masks are a must. You might also want to wear long pants and sleeves. Remember, you’re not just protecting yourself from mould, but also from any of the chemicals you’ll be using to clean.
Be sure that anyone with respiratory issues (such as asthma) is kept well away during the process.
2. Grab your cleaning products
There are several options when it comes to cleaning mould from air conditioner vents. These include:
- Laundry detergent
- Dish soap
- Detergent plus baking soda (ratio of one tablespoon detergent to half a tablespoon soda, added to one cup of water)
- Bleach (one part bleach to 16 parts water). Please be aware that bleach is recommended for non-porous surfaces only.
- Other commercial mould killers
You’ll also need some rags for cleaning and scrubbing and a spray bottle to help clean the inside of the system. You may also want to grab a HEPA vacuum to pick up any dust or debris inside the unit, as well as after the clean is done.
3. Start cleaning!
- Turn off the unit and unscrew the vents.
- Mix up your chosen solution in a large basin and submerge the vents.
- While the cleaning products work their magic, vacuum inside the unit, before giving the interior a good spray with cleaning solution. Scrub the insides thoroughly.
- Dry with a clean rag.
- After about 15 minutes, remove the vents from the solution and scrub clean.
- Dry with a clean rag.
- Reattach the vents.
- Wipe down and dry the outside of the unit.
Once cleaned, there is plenty you can do to help prevent mould from taking root in the future. Prevention is, after all, the best cure.
Start by keeping the exterior of your air conditioner unit clean by wiping down its surfaces weekly and clearing away any dust and debris lingering around its intake.
You should also ensure that nothing is blocking the air flow to or from the unit, and that you are replacing filters regularly. You can also schedule regular inspections from a professional to ensure everything is clean and working properly.
If you live in a humid area, you may want to look into purchasing a dehumidifier. This will help keep moisture levels down and add an extra layer of protection against mould.
What if the mould has spread too far or looks particularly dangerous?
Removing mould from air conditioner vents can be a time-consuming job, and if it looks like your vents might be too far gone, you can look at replacing them entirely.
You can do this yourself—while giving the unit a good clean, of course—or call in a professional to do it for you.
If you believe the mould to be dangerous (especially if it shows signs of being black mould), be sure to contact a professional to assess the situation.
And that’s how you clean mould from air conditioner vents!
For more on keeping your air conditioner at its best, be sure to check out some of our other posts. We recommend our Quick & Easy Guide to Cleaning Your Air Conditioner, and Why Does My Aircon Smell? – seven suggestions on what might be causing your air conditioning unit to emit a strange smell!
- Beth McCallum, 2021, Seven Ways to Remove Mould on Air Vents, Oh So Spotless
- Michael Rosone, 2020, Mold in Air Ducts? How It Got There & How To Get Rid of It, Arista
- Judith Evans, 2018, How to Clean Black Mold on Air Conditioner Vents, SF Gate