1. Wrong mode or setting
The remote may be on Fan, Dry or Auto mode, or the temperature is set too high.
How we fix itFree: set Cool mode, 24–25°C
SAMPLE DEMO · An example of the template filled with real content.See the blank template →All templates
Why Is My Aircon Not Cold?
An aircon that runs but doesn't cool is one of the most common problems in Singapore homes. Here's how to find the cause and what it costs to fix.
The short answer
An aircon that runs but isn't cold is usually caused by a dirty filter or coil, low refrigerant gas, or a dirty outdoor unit. First check the mode and temperature on the remote and clean the filter. If it's still warm, it needs servicing or a gas top up.
Quick diagnosis: what is your aircon doing?
| What you notice | Likely cause | Fix | Cost |
|---|---|---|---|
| Weak airflow, filter looks dusty | Dirty filter or coil | Clean filter (DIY) or general servicing | Free / from $54.50 |
| Air is cool, not cold, and getting worse | Low refrigerant gas | Gas top up and leak check | from $100 |
| Outdoor unit fan not spinning | Outdoor fan motor or capacitor fault | Repair after diagnosis | $80 diagnosis* |
| Fan blows but no cold air at all | Compressor or capacitor fault | Repair after diagnosis | $80 diagnosis* |
| Weak cooling plus musty smell | Mould-clogged coil | Chemical overhaul | from $150 |
Prices before GST. *On-site diagnosis is $80 for a split system and is waived when you book the repair.
5 reasons your aircon is not cold, and how to fix each
2. Dirty filter and coil
Dust on the filter and coil stops air from passing over the cold coil, so less cold air comes out.
How we fix itFilter and coil cleaningAircon servicing from $54.50 →
3. Low refrigerant gas
Without enough gas the coil can't absorb heat. Gas only runs low when there's a leak, so the leak should be found first.
How we fix itLeak check and gas top upGas top up from $100 →
4. Dirty or blocked outdoor unit
The outdoor unit releases heat. If its coil is dirty or blocked by items, the system can't cool properly.
How we fix itOutdoor unit cleaningAircon servicing from $54.50 →
5. Faulty capacitor or compressor
If the outdoor unit hums but doesn't start, a capacitor or compressor part may have failed.
How we fix itDiagnosis, then part replacementAircon repair: $80 diagnosis →
What you can check yourself
- Set the remote to Cool mode at 24–25°C.
- Clean the filters and let them dry fully.
- Clear the outdoor unit of anything blocking airflow.
- Close doors and windows in the room.
- Wait 15 minutes and feel the air again.
Don't try to top up gas yourself. It needs proper tools and a licensed technician.
Aircon not cold: FAQs
How much does it cost to fix an aircon that's not cold?
At JL Aircond, general servicing starts from $54.50 per unit and a gas top up from $100, before GST. If a part has failed, the $80 diagnosis fee is waived when you book the repair.
Why is my aircon running but not cold?
The most common reasons are a dirty filter or coil, low refrigerant gas, or a dirty outdoor unit. A faulty capacitor or compressor is less common but needs a technician.
How often should I top up aircon gas?
Aircon gas shouldn't need regular top ups. If it's low, there's usually a small leak that should be found and fixed first.
Can a dirty aircon stop cooling?
Yes. A dirty filter or coil can cut cooling a lot. Regular servicing every 3 to 4 months keeps it working well.
Aircon still not cold? We'll fix it.
Tell us your aircon brand and what it's doing on WhatsApp. We'll tell you the likely cause and give you a quote.