Why is my air conditioner not cooling?

By South West Tech

Check the Basics First

If your air conditioner isn't cooling properly, the cause can be something as simple as a dirty filter or as complex as a refrigerant leak or failing component.

Before assuming the system needs replacing, there are a few simple things you can check yourself. Many cooling issues are caused by a lack of routine maintenance rather than major faults.

Start by making sure the air conditioner is set to Cooling Mode rather than Fan or Heating, and that the temperature is set lower than the current room temperature.

Next, inspect the indoor air filters. Dirty filters are one of the most common reasons an air conditioner struggles to cool a room. When filters become clogged with dust, airflow is restricted, forcing the system to work harder while delivering less cooling.

If the filters are dirty, switch the unit off, remove them and gently wash them according to the manufacturer's instructions. Once dry, reinstall them and test the system again.

It's also worth checking that the outdoor unit isn't blocked by leaves, grass, weeds or other debris, as restricted airflow can significantly reduce performance.

When a Filter Clean Isn't Enough

If you've cleaned the filters and the air conditioner still isn't cooling properly, the problem may require professional attention.

Over time, dust, mould and grime can build up deep inside the indoor unit, particularly on the evaporator coil and fan barrel. These components can't be properly cleaned without dismantling the unit and using specialised equipment.

Other possible causes include low refrigerant, blocked drains, faulty sensors, electrical faults or worn components. These issues require diagnosis by a qualified technician.

When Should You Book a Professional Service?

If your air conditioner is blowing warm air, takes much longer than usual to cool the room, has weak airflow, is leaking water, making unusual noises or producing unpleasant smells, it's time to arrange a professional service.

A professional air conditioner clean removes dirt and mould from areas you can't safely access yourself while also checking the system's electrical components, refrigerant performance, drainage and overall operation.

For homes throughout rural Queensland, where dust and high temperatures place extra demand on air conditioners, South West Tech recommends cleaning your filters regularly and booking a professional air conditioner clean and service every 12 months. Regular servicing helps keep your system cooling efficiently, reduces running costs and can prevent small problems from turning into expensive repairs.