Air conditioning systems constantly deal with temperature changes and moisture, and they can easily become the perfect breeding ground for mould.
If you notice a musty, damp smell when you turn your system on, mould has likely already started growing inside the unit. Fortunately, keeping your system clean and free from mould and other pollutants is straightforward. Here is exactly why mould forms inside an air conditioner, and how you can prevent it.
Why Does Mould Grow in an Air Conditioner?
Mould needs three things to thrive: warmth, darkness, and moisture.
When your air conditioner cools a room, it pulls moisture out of the air. This moisture condenses into water droplets on the internal cooling coils. Under normal conditions, this water drips into a drain pan and flows safely outside.
However, if dust settles on those wet internal parts, or if moisture sits stagnant inside the machine for too long, mould spores will root and multiply. When you turn the fan back on, those spores are blown straight into your living space.
4 Practical Ways to Prevent AC Mould
1. Run “Fan Only” Mode Before Shifting Seasons
If you only use your system for cooling during hot weather and plan to leave it off for months at a time, do not just switch it off and walk away. Dust and trapped moisture will settle inside the stagnant components.
- The Fix: Once a month or right before you turn it off for a long period, run the system on “Fan Only” mode for 20 to 30 minutes. This circulates room-temperature air through the unit, completely drying out the internal coils and preventing autumn mould growth.
2. Schedule Professional Filter Maintenance and Book an Annual Deep Clean
Your aircon filters trap dust, hair, and airborne debris. If the filters are choked, two things happen: airflow is restricted (causing the system to stay damp longer), and dust bypasses the filter to settle directly onto the wet cooling coils. This dust acts as food for mould.
- The Fix: Trying to DIY filter maintenance can damage delicate clips, void your warranty, or leave internal components improperly sealed. Schedule a brief service visit or annual strip-clean with JC Refrigeration to keep the system running efficiently and mould-free.
3. Clear the Outdoor Unit and Condensate Drain
The moisture collected by your indoor unit relies on a small drain pipe to carry the water away. If this drain gets blocked by dirt, algae, or outdoor debris like dead leaves, the water backs up and pools inside your indoor unit.
- The Fix: Ensure your outdoor unit has at least 50cm of clear space around it. If you notice water dripping from the indoor unit’s casing instead of the outside drain pipe, turn the system off immediately and call a technician to clear the blockage before mould sets in.
The Takeaway
Preventing mould inside your air conditioner comes down to managing moisture and dust. By staying up to date with preventative maintenance and taking 20 minutes to dry out the coils once a month, you can keep your indoor air fresh, healthy, and completely odour-free.
If your system already has a persistent damp smell, a standard filter clean won’t fix it. Contact JC Refrigeration today to book a professional deep clean and protect your indoor air quality.