Why Is My Aircond Not Cooling? 5 Causes and Fixes

Running but Not Cooling? Don't Panic.

This is the most common complaint we get: "the aircond is on, but the air isn't cold like it used to be." Before you start pricing a replacement, work through these five causes. Most are solved by ordinary servicing.

Cause #1: A Filter Clogged with Dust

The most common cause, and the easiest to fix. The filter traps dust from the air; left uncleaned it chokes airflow and the unit cannot move cold air into the room.

The fix

• Open the front panel and slide the filter out
• Rinse it under a tap, brushing gently with a soft brush
• Dry it completely before refitting
• Repeat every 2-3 weeks for best performance

If the filter is clean and it still is not cooling, move on.

Cause #2: Low or Empty Refrigerant

Your unit needs refrigerant gas — R32 on newer models, R410A on older ones — to cool at all. When the charge is low, the unit blows lukewarm air even with the compressor running.

Signs of low gas

• Warm air even with the setpoint at 16°C
• Ice forming on the outdoor unit's pipework
• The compressor short-cycling on and off repeatedly

The fix

You cannot do this yourself — a technician has to top it up. An R32 top-up runs RM120-180. Important: if the gas keeps running low there is a leak, and the leak has to be found and sealed first.

Cause #3: A Dirty Evaporator Coil (Chemical Wash Needed)

The evaporator coil inside the indoor unit is what absorbs heat. Once it is coated in dust and grime, cooling performance falls off a cliff.

Signs

• The filter is clean but it still is not cooling
• A musty or sour smell
• An unexplained rise in the electricity bill

The fix

Book a technician for a chemical wash, RM130-180 per unit. Read more about the signs you need one here.

Cause #4: The Unit Is Undersized for the Room

If the unit has been serviced and still cannot hold temperature, the horsepower may simply be too low for the space.

How to check

Measure the room and compare against our HP sizing guide. A 1.0HP unit in a 350 sqft room was never going to work — that room needs 2.0HP.

Cause #5: A Compressor or Capacitor Fault

If everything above checks out and the unit still is not cooling, the fault is likely mechanical — a weak compressor, a failed capacitor, or a problem on the PCB.

Signs of a mechanical fault

• The outdoor unit is completely silent — the compressor never starts
• Clicking, but no compressor start
• An error code on the remote or the unit's display

The fix

This needs a technician's diagnosis. Repair costs depend on the fault: a capacitor is RM80-150, a PCB RM200-500, a compressor RM800-1,500 — and on a Daikin the compressor is usually still under its 5-year warranty.

Before You Call — Three Quick Checks

• Wash the filter — free, and you can do it yourself
• Check the setting — make sure it is on cool at 16-20°C, not fan mode
• Clear the outdoor unit — airflow around it must not be blocked

Still not cold after those three? Then it is time for a technician.