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Mould in airconiditioner

Mould in the Air Conditioner? Here is How to Tackle It

, by Aussie Pharma Direct, 8 min reading time

As the hot season descends upon Australia, or the rain-soaked months make their presence felt, our reliance on air conditioners becomes more than a comfort—it's a necessity. Amid the rhythmic hum of these cooling technology, however, a silent threat often goes unnoticed: mould growth within the confines of your air conditioner.

We'll navigate the signs that may signal mould presence, explore the potential health implications heightened by the weather conditions, and, most significantly, provide you with effective strategies for cleaning and maintaining your air conditioner.

What causes mould in an air conditioner?

It's essential to first understand how and why mould can take root in these seemingly indispensable cooling systems.

Moisture accumulation:

Mould, being a resilient organism, thrives in environments with elevated moisture levels. The constant operation of air conditioners results in the condensation of moisture from the air. This condensed water, if not properly drained or directed away, accumulates within the unit, creating an ideal breeding ground for mould.


The internal components of air conditioners undergo temperature fluctuations as they cool and dehumidify the air. This process can lead to condensation on various surfaces within the unit. Over time, this persistent dampness becomes a catalyst for mould development, especially if coupled with inadequate ventilation or drainage.

Dust and debris:

As the air conditioner draws in air from its surroundings, it inevitably pulls in airborne particles, including dust and debris. These minute contaminants can settle within the unit, providing an additional food source for mould. When combined with moisture, the stage is set for mould spores to germinate and multiply.

Can mould in an air conditioner make you sick?

The unequivocal answer is yes. The health implications of breathing air contaminated with mould from your AC include:

1. Respiratory issues

Mould spores, once airborne, can be inhaled into the respiratory system. This inhalation poses a particular risk for individuals with pre-existing respiratory conditions such as asthma or chronic bronchitis. Even for those without prior respiratory issues, exposure to mould-infested air can lead to symptoms like coughing, wheezing, or shortness of breath.

2. Allergies

Mould is a recognised allergen, capable of triggering allergic reactions in susceptible individuals. Symptoms such as sneezing, nasal congestion, itchy or watery eyes, and skin irritation are common outcomes of exposure to mould-laden air. Continuous exposure through the AC system can intensify these allergic responses.

3. Other symptoms

The repercussions of prolonged exposure extend beyond respiratory and allergic reactions. Headaches, fatigue, and difficulty concentrating are reported by some individuals exposed to elevated levels of mould spores.

What does mould in an air conditioner look like?

Here are key signs of mould in your air conditioner to watch for:

  • Musty odours - Earthy smells emanating from the vents when the unit is in operation.
  • Visible mould - Check the interior components of your air conditioner, such as coils, filters, and drip pans, for any signs of mould growth. Mould can manifest in various colours, including green, black, or brown.
  • Reduced cooling efficiency - Mould can accumulate on the evaporator coils and other components, hindering the efficiency of your air conditioner.

How to clean mould in the air conditioner?

Here's a step-by-step guide to clean mould from air conditioner and maintenance, along with the use of SAN-AIR mould removal products for an added layer of protection.

1. Gather necessary supplies such as:

  • Protective gears like gloves and masks
  • SAN-AIR mould removal products - Surface Mould Remover, and Household Grade Disinfectant
  • Basic tools, including a screwdriver, a soft brush, and a vacuum cleaner

 2. Turn off the AC 

  • Safety should always be the priority. Before you commence cleaning, turn off the power to your air conditioner.

3. Cleaning the filters

  • Gently detach the air filters from the unit. Refer to your AC manual for guidance on filter removal.
  • Depending on the type of filter, either clean it using a soft brush or replace it with a new one.

4. Cleaning coils and drip pans

Mould often finds a haven on coils and in drip pans. To effectively clean these components, utilise SAN-AIR Surface Mould Removal for a comprehensive approach. 

  • Spray SAN-AIR Surface Mould Removal generously on coils and drip pans.
  • Allow the solution to sit for 10 minutes, letting it break down and eliminate mould.
  • Wipe surfaces with a clean cloth or sponge to remove loosened mould, making sure to change the cloth frequently as you do. .
  • Once clean, lightly spray again and let components air dry.

5. Ensure proper drainage

  • Inspect drain channels for blockages.
  • Clear debris and use a wet/dry vacuum to remove stubborn clogs.
  • Check the alignment and slope of drain channels for optimal water flow.
  • Consider using a drain pan treatment to prevent algae and mould growth.

6. Vent and duct inspection

  • Turn off the HVAC system.
  • Remove vent covers and soak them in soapy water.
  • Vacuum vent openings to remove dust and debris.
  • Inspect duct interiors with a flashlight and mirror for any signs of mould growth or excessive dust accumulation.
  • Clean vent covers with a soft brush or cloth, rinse, and air dry.
  • Wipe accessible duct interiors, utilising the SAN-AIR Surface Mould Remover in a similar way as you did with the coils and drip pans.
  • For added assurance, wipe SAN-AIR Household Grade Disinfectant inside the ducts. This helps neutralise any remaining mould spores and bacteria.
  • Replace vent covers securely.

7. Final steps

  • Monitor the system regularly for any signs of mould or issues.
  • Schedule professional HVAC maintenance periodically for a thorough inspection.
  • Consider professional duct cleaning if significant mould or dust issues persist.

How to prevent mould in an air conditioner?

Preventing mould growth in your air conditioner involves regular inspection and cleaning. In general,

  1. Check and, if necessary, clean or replace air filters every 1 to 3 months. 
  2. Perform a visual inspection of vents and ducts at least once a year.
  3. Place a new SAN-AIR™ V3R Split System Reactive Gel behind the machine filter of your air conditioner every 10-12 weeks for ongoing mould prevention. Ensure secure positioning that does not obstruct airflow.

Limiting the use of your air conditioner when not necessary is also an effective strategy for mould prevention. 

Mould thrives in moist environments, and reducing the operating time of your air conditioner during cooler or less humid periods helps keep internal components dry. This practice, combined with regular ventilation and the use of alternative cooling methods when appropriate, contributes to a healthier indoor environment by discouraging mould growth.

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