Why is my AC Not Cooling or Blowing Cold Air

If your split system is running but the air is not cold, the most common cause is restricted airflow. A clogged filter or dirty indoor coil stops heat transfer, so the unit cannot remove heat from the room. Start with the quick checks below. If cooling is still weak, do a proper clean to restore airflow.

Quick checks to try first

Make these simple checks before you pull anything apart.

• Confirm the unit is in Cool mode, not Dry or Fan
  
• Set the temperature at least 3 to 4°C below room temperature
  
• Set fan speed to Medium or High
• Close doors and windows and reduce direct sun if possible
• Check for error lights or codes on the indoor unit
  
  

If air is still not cold, you are likely dealing with a dirty filter, coil or blower.

Why airflow problems kill cooling

Dust on filters, coils and the blower acts like a second filter inside the unit. Less air passes over the coil, so less heat is removed. In bad cases the coil ices up and blocks airflow completely.

What you may notice

• Weak airflow from the indoor head
• Musty or dusty smell at start up
• Room never reaching set temperature
• ice on the indoor coil or water dripping after it thaws
• Long run times and higher power use
  
  

The fix is to clean both the filters and the inside of the unit, not just the grille.

How to get the cold air back

You can restore cooling with a thorough clean that removes dust and biofilm from the parts that matter.

1. Turn power off at the isolator or breaker
2. Remove and rinse the filters, then let them dry
3. Protect walls and floors with a catch bag
4. Apply coil cleaner to the indoor coil and fan
5. Brush away loosened build up
6. Rinse thoroughly and let the unit dry
7. Reassemble and test on Cool with Medium fan
   
   

Everything you need is in the DIY Air Conditioner Cleaning Kit. It includes coil cleaner, brushes, a pump bottle for rinsing, microfibre cloths, a collapsible bucket and a catch bag.
DIY Air Conditioner Cleaning Kit

For the full step by step walkthrough, use the official guide.
Split System Aircon Cleaning Kit Guide

Helpful internal resources

If you want a condensed tutorial, read our AC cleaning guide for a simple, repeatable process.
AC cleaning guide

To understand the real costs and health risks of skipping maintenance, see what happens if you don’t clean your AC.
What happens if you don’t clean your AC

Other reasons an AC will not blow cold

If a full clean does not fix it, consider these additional causes.

• Iced evaporator coil from severe airflow restriction. Turn the unit off and let the ice thaw before restarting
• Blocked outdoor coil or fan slowed by lint or debris. Clear obstructions and ensure space around the outdoor unit
• Clogged drain tray or float switch trip that stops operation until water drains
• Thermostat or sensor in direct sun or a draft that skews readings
• Low refrigerant or a mechanical fault such as a failing compressor or expansion device. These require a licensed technician
  
  

How to prevent repeat cooling problems

Keep airflow healthy with a simple maintenance routine.

• Check filters monthly in peak seasons
• Rinse filters every one to two months
• Do a full kit clean every three to six months, or before summer and before winter
• Keep return and supply paths clear of curtains and furniture
• Maintain clear space around the outdoor unit
  
  

This is why we created our AC cleaning kit. It helps you and your system stay healthy and efficient by keeping the airflow path clean and free flowing. Use the kit and follow the guide to bring back reliable, cold air.