Aircon Troubleshooting · Singapore
Why Is My Aircon Not Cold?
If your aircon runs but doesn’t blow cold air, it’s almost always one of three things: low refrigerant, a clogged coil, or a dirty condenser. Here’s how to tell which — and how we fix it.
The short answer
An aircon that runs but won’t cool has usually lost its ability to move heat. Low refrigerant is the single most common cause, followed by a clogged indoor coil or a dirty outdoor condenser. Less often, it’s a compressor or electrical fault. Try the quick checks below first; if cooling is still weak, it needs a technician.
Common causes — and the fix for each
From most to least common in Singapore homes.
Low refrigerant (gas leak)
The most common cause. When refrigerant leaks out, the system runs but can’t carry heat away — so air feels weak or only slightly cool. Often paired with ice on the copper pipes or a hissing sound.
Gas top-up from $80Clogged filter or evaporator coil
A dirty filter or mould-caked indoor coil blocks airflow, so cold air can’t get out. Common in Singapore’s humidity if the unit hasn’t been deep-cleaned in a while.
Chemical wash from $110Dirty outdoor condenser
The outdoor unit rejects your room’s heat. When its coil clogs with dust, heat can’t escape and cooling fades — even if the indoor unit looks clean.
Condenser cleaning from $50Compressor or electrical fault
If the compressor isn’t kicking in — or a capacitor, sensor, or PCB has failed — the system can’t cool at all. This needs diagnosis with proper tools.
Aircon repair from $50What you can check yourself first
These are free and safe to try before booking a visit.
- 1Set the mode to “Cool” (a snowflake icon) — not “Fan” or “Dry” — and drop the temperature to 24°C or below.
- 2Replace the remote batteries; a weak remote can fail to send the cool command.
- 3Remove and rinse the washable filter — a clogged filter chokes airflow.
- 4Check the outdoor unit isn’t blocked by laundry, boxes, or debris, and that the breaker hasn’t tripped.
When to call a technician
If the air is still warm after the checks above, the problem is inside the sealed system — low refrigerant, a clogged coil, or an electrical fault — and none of those are safe or possible to fix without tools and training. The longer a unit runs low on gas, the harder the compressor works, which can turn a cheap top-up into an expensive compressor replacement.
We diagnose the exact cause on-site, tell you the price before any work, and can usually fix it the same day. Servicing across Singapore from $45.
Other aircon problems
Aircon not cold — FAQs
Why is my aircon running but not cold?
Does aircon gas run out over time?
How much does it cost to fix an aircon that is not cold?
Can I fix my aircon not being cold myself?
Still not cooling? We’ll sort it today.
Same-day diagnosis across Singapore. Transparent pricing — you know the cost before we start.