Air conditioning in a hot and humid climate like Brisbane and Queensland is an essential for year round comfort. However, if you’ve noticed an unpleasant, musty smell coming from your air conditioner, it could be an indication that mould or mildew is growing somewhere inside the unit. This is not a problem to put off or ignore as contaminants in your air conditioner can lead to poor air quality, and health problems for your household.

There are a number of possible causes of a musty smelling air conditioner, from excess moisture within the unit, to an oversized air conditioner that is unable to properly dehumidify. Below are the most common causes of a musty smelling air conditioner and how to fix them.

Excess Moisture In Ducts Or Vents

One reason for musty smelling air coming from your air conditioner is if there is a build up of excess moisture in the ducts or vents. In humid climates like we have in Queensland, the moisture in the air can cause excess moisture to build up inside the air ducts and vents of your air conditioning system.

Unfortunately, the dark and damp environment created by the build up of moisture inside the system is an ideal place for mould and mildew to form. Not only will this cause the musty smell coming from your air conditioner, it can also affect the air quality in your home as contaminants are circulated through the air. This is particularly harmful in households with children, elderly, or anyone with respiratory conditions, so it’s important to address the problem as soon as possible.

How To Fix It

The best way to ensure that any mould or mildew is completely cleared out of your air conditioning system is a professional air duct cleaning service. In addition, schedule regular servicing for your air conditioner to prevent moisture buildups in the future.

Dirty Filters

Air conditioners use filters to remove dust, dirt, and other pollutants from the air before circulating it into your home. As with most filters, the air filters in your air conditioner need to be cleaned or replaced regularly to allow air to flow freely through them.

Air filters that are left unchanged for too long can become clogged with dirt and dust. This can hinder airflow and cause moisture from the humid air to collect on the evaporator coil, allowing mould and mildew to grow.

How To Fix It

If there is mould growing on your evaporator coil you will need to book a service to have the inside of the air conditioner professionally cleaned. After your air conditioner is clear of any mould or mildew it should no longer give off a musty smell when running.

However, it’s important to regularly change the filters in your air conditioner to prevent the problem from arising again. If you’re not sure how to do this, ask your air conditioning technician to show you during the service. You will also need to purchase replacement filters that fit your air conditioner. These can be ordered through your AC technician or picked up at your local hardware store.

Overfull Drip Pan

As air conditioners are used to not only cool air, but also to extract moisture from humid air, they need a place for the extracted moisture to be collected, this is called the drip pan. However, sometimes the drip pan can become rusted or damaged, failing to collect the extracted moisture from the air. This can result in moisture build up inside the air conditioner leading to mould growth and causing a musty smell.

How To Fix It

Luckily, an air conditioner drip pan is typically inexpensive to replace and can be found at most hardware stores. Make sure to take a photo of your air conditioner’s drip pan before heading to the store to ensure that you purchase the right one. If you’re not sure of the right type of drip pan to buy or can’t find the one you need, contact your local air conditioning technician to have them order one for you.

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Clogged Drain Pipe

Once water is collected in the drip pan it is drained outside via a small drain pipe that can be found next to the outdoor unit. Due to the dark and moist environment of the drain pipe, it is a prime place for mould to grow. Additionally, the pipe may become clogged which can also give off a musty smell.

How To Fix It

Ensuring that your drain pipe doesn’t become clogged is as simple as cleaning it out once a month. When cleaning the drain pipe of your air conditioner, make sure that all power to the air conditioner is turned off (including at the switchboard). If you’re not sure how to safely clean it, book a service with your local air conditioning specialists.

Oversized AC

Another possible cause of a musty smelling air conditioner is if your air conditioner is too large for the space that it is cooling. An oversized air conditioner can cool the area too quickly, before the air cycle is complete. This can result in the air conditioner shutting off before the air is properly dehumidified, leaving humid air to circulate the house. This can cause mould and mildew growth, resulting in an unpleasant musty smell.

How To Fix It

To avoid installing an oversized air conditioner that will run up your electricity bill and leave the room feeling uncomfortable and clammy, talk to your local air conditioning company about choosing the right sized air conditioner for your needs.

Your Local Air Conditioning Experts

Advanced Climate Solutions are your local air conditioning experts. If you’ve noticed a must smell coming from your air conditioner, call us today on 07 3206 3542 for expert advice or to book a service. We also offer quality air conditioning installations and repairs Brisbane wide. Choose ACS for all of your Brisbane air conditioning needs.