7 Signs Of Mould In Aircon

Efficient Hygiene Services • June 19, 2024

Spotting mould in your air conditioner isn’t just about an unsightly black or green growth; it’s a potential health hazard that can affect the air quality of your entire home. Mould thrives in damp, dark places, making your air conditioning unit an ideal breeding ground if not maintained properly. In this blog post, we’ll walk through seven signs that your air conditioner might be harbouring mould.


1. Unpleasant Odours Emanating from the Unit


One of the most noticeable mould signs in air conditioners is an unusual odour that permeates the air. This musty smell is often the first indicator of mould presence.


  • Musty Smell: A persistent musty odour similar to damp socks or wet cardboard.
  • Location of Smell: Strongest near the air conditioning vents and units.
  • Consistency: The smell is consistent, becoming more noticeable when the unit is running.


This characteristic smell arises because mould, thriving in damp environments, releases gases known as microbial volatile organic compounds. These gases are not only unpleasant but can also be harmful to your health.


2. Visible Black or Green Patches


Aircon mould often manifests as distinct black or green patches within the air conditioning unit. These patches can appear on the filters, vents or even deep within the ducts. Mould tends to grow in places with high moisture content, such as condensation trays or near evaporator coils.


Regular checks can prevent mould from spreading and affecting the air quality in your home. These visual signs of mould in the air conditioner are a clear indicator of a high moisture level within the unit, which can be due to issues like leaks or poor drainage.


3. Increased Allergy Symptoms


Mould in air conditioning systems can significantly aggravate allergy symptoms. This connection is crucial to recognise for maintaining indoor air quality:


  • Allergic Reactions: Common reactions include sneezing, runny nose, red eyes and skin rash. Additionally, mould can also trigger asthma attacks and exacerbate chronic respiratory conditions.
  • Symptom Triggers: These symptoms often worsen when the air conditioner is in use, indicating mould spores are circulating in the air. Addressing this promptly is essential, as continual exposure can lead to more severe health issues.


Regular cleaning of the air filter and servicing can help minimise these symptoms by reducing mould exposure. Ensuring that ducts and vents are inspected and cleaned can further mitigate the risk of mould-related health problems.


4. Frequent Respiratory Issues


Mould in air conditioning systems can lead to more severe respiratory issues, particularly in individuals with pre-existing health conditions. Mould spores can irritate the airways, leading to symptoms such as wheezing, difficulty breathing and chest tightness. These symptoms can be more severe in asthmatic individuals.


Frequent respiratory issues in family members, especially those without prior respiratory conditions, can also indicate mould problems. This necessitates immediate action to ensure the home environment remains safe and healthy.


5. Unexplained Humidity Increase


Increasing indoor humidity levels can be a subtle sign of a mould issue in your air conditioner. Here’s how it affects your environment:


  • Efficiency Loss: Mould can block airflow and lead to less effective cooling and dehumidification, straining your system and increasing energy usage.
  • Moisture and Mould: High humidity supports mould growth, perpetuating a cycle of humidity and mould issues.


This ongoing cycle can degrade air quality and damage interior surfaces over time.


6. Unusual Sounds from the Air Conditioner


Mould growth can lead to blockages in the aircon system, which may cause unusual sounds. It can accumulate in the ducts or on the coils, leading to clogs that strain the aircon’s motor and fan. This strain can produce rattling, buzzing or whistling noises.


These sounds indicate that a thorough inspection is necessary to clear out any obstructions and accumulated mould, ensuring the unit operates smoothly without disruptions. Regular acoustic checks of the unit during maintenance can help detect these issues early, making it easier to address them before they lead to significant repair needs or system failures.


7. Poor Cooling Performance


Mould can severely impact the cooling performance of your aircon, signalling a need for professional inspection and cleaning.


  • Symptoms of Poor Performance: Reduced airflow, uneven cooling or the unit struggling to maintain set temperatures. Over time, these symptoms can lead to increased discomfort, particularly during hot weather.
  • Mechanism: Mould and debris can block the air filters and coils, reducing the system’s efficiency. This blockage prevents the air conditioner from exchanging heat effectively, which is crucial for proper cooling.


Regular cleaning and maintenance to restore optimal function. Establishing a routine service schedule can prevent mould and ensure your aircon remains efficient and effective year-round.


Dealing with Mould Problems? We Can Help!


At Efficient Hygiene Services, we understand the nuances of maintaining a healthy, mould-free air conditioning system. We encourage you to not overlook these signs. If you suspect mould in your air conditioner, get in touch via our contact page or give us a call for more information or to book a consultation or service. Our expertise ensures your air conditioning system runs efficiently and supports a healthy indoor environment.


Find Efficient Hygiene Services here.


Recent Posts

Metal air duct interior with a fan, showing dust and debris buildup.
By Efficient Hygiene Services August 15, 2025
Dust, mould and allergens lurk in dirty systems. Learn what to watch for and when to schedule HVAC cleaning Gold Coast. Breathe easier—act now.
Person in blue gloves using a screwdriver on an air conditioning unit.
By Efficient Hygiene Services August 11, 2025
Save costs and avoid storage hassles. Discover why Air Scrubber Hire Gold Coast is ideal for short-term use. Get started today.
Person removing an air filter from a white air conditioning unit mounted on a wall.
By Efficient Hygiene Services August 8, 2025
Protect your pets from hidden dangers. Get expert air conditioner cleaning in Gold Coast and Brisbane. Book professional air con cleaning today.
Person attaching a blue pressure gauge to a brass fitting on a gas cylinder.
By Efficient Hygiene Services March 3, 2025
Discover the benefits of air quality testing in Gold Coast and Brisbane. Improve workplace health, boost productivity, and stay compliant.
Ceiling fan with five blades inside a metal duct.
By Efficient Hygiene Services February 28, 2025
Spot the signs to clean your kitchen exhaust. Ensure safety with expert exhaust fan cleaning in Brisbane & Gold Coast. Act now to prevent risks.
Greasy interior of a metal industrial ventilation system.
By Efficient Hygiene Services January 23, 2025
Regular cleaning exhaust fan maintenance prevents fire hazards, improves air quality, and ensures system efficiency. Learn more today!
Close-up of a dirty, opened air conditioning unit, showing the internal cooling fins.
By Efficient Hygiene Services January 20, 2025
Improve air quality and efficiency with professional air conditioner cleaning. Book a service today for a healthier and cleaner environment.
Inside of an air duct, coated in thick white dust and debris, with visible clips.
By Efficient Hygiene Services January 16, 2025
Prevent costly HVAC system breakdowns with expert HVAC cleaning in Gold Coast and Brisbane. Ensure efficiency with regular maintenance today.
Blue motor and fan inside a ventilation duct, dark walls.
By Efficient Hygiene Services November 4, 2024
Get peace of mind with effective mould remediation. Discover key questions to ask your team for quality results. Protect your space today!
Comparison of a dirty, stained ceiling with a clean, freshly painted ceiling. A light fixture is centered.
By Efficient Hygiene Services November 1, 2024
Learn the health impacts of mould exposure and how to protect both your health and your property. Contact us today today to learn more.
Show More