There’s nothing worse than an air conditioner that’s running but not actually cooling the room — especially during a Brisbane summer. Before you call for help, there are a few simple things worth checking. Here are the most common causes and what to do about each.
1. Dirty or blocked filters
This is the number one cause. When filters clog with dust, airflow drops and the unit can’t cool effectively. Pop out the filters on the indoor unit, give them a clean, and let them dry before refitting. If you haven’t done this in months, it can make an immediate difference.
2. Incorrect settings
It sounds obvious, but check the remote is set to Cool (the snowflake symbol), not Fan or Dry mode, and that the temperature is set well below the room temperature. A unit in Fan mode just blows air without cooling it.
3. The outdoor unit is blocked or dirty
Your outdoor unit needs clear airflow to release heat. If it’s covered in leaves, surrounded by plants, or caked in dirt, it can’t do its job. Clear away any debris and make sure there’s space around it.
4. Low refrigerant or a leak
If the system runs constantly but only blows slightly cool or warm air, it may be low on refrigerant, often due to a leak. This is not a DIY fix — refrigerant handling is regulated and requires a licensed technician with an ARCtick licence. Topping up without fixing the leak is also a waste of money.
5. Iced-up coils
If you see ice on the indoor unit or pipes, switch the system off and let it fully defrost. Frozen coils are usually caused by restricted airflow (dirty filters) or low refrigerant, so it often points back to one of the issues above.
6. Electrical or capacitor faults
If the outdoor unit isn’t running at all, or trips the power, it could be a capacitor, fan motor or electrical fault. These need a qualified technician to diagnose safely.
What you can check vs when to call a pro
You can safely clean filters, clear the outdoor unit, and check your settings. Anything involving refrigerant, electrical components or opening up the unit should be left to a licensed technician — both for safety and because incorrect work can void your warranty.
Get your air conditioner working again
If the simple checks haven’t fixed it, Integrated Trade Services repairs and services split and ducted systems across Brisbane, with licensed and ARCtick-certified technicians. See our air conditioning services or call 0400 775 002.