Why Is Your Aircon Not Cold? The Top 7 Reasons in Singapore

In Singapore's 30–33°C heat, an aircon that stops cooling is more than uncomfortable — it's a health risk. Before you panic, here are the 7 most common reasons your aircon is blowing warm or barely cool air, and exactly what to do about each one.

Reason 1: Dirty Air Filter

The most common cause. When the air filter is clogged with dust, airflow is restricted and the evaporator coil cannot cool air efficiently. Fix: Clean the filter yourself (rinse with water) or call AOT for a general aircon service from $35/unit.

Reason 2: Low Refrigerant Gas

If your aircon has a slow refrigerant leak, it won't be able to cool effectively no matter how low you set the temperature. Signs: the unit blows air but it's not cold; ice may form on the evaporator. Fix: Gas top-up service from $80. Our technicians check for leaks first to prevent repeat issues.

Reason 3: Dirty Evaporator or Condenser Coils

Over time, the evaporator (indoor) and condenser (outdoor) coils accumulate dirt and grime, dramatically reducing heat exchange efficiency. Fix: Chemical wash from $80/unit — restores up to 85% of original cooling performance.

Reason 4: Oversized or Undersized Unit

If your aircon is too small for the room, it'll run continuously but never fully cool the space. If it's too large, it short-cycles. Fix: Our technicians can assess whether your unit is correctly sized for your room (BTU calculation).

Reason 5: Faulty Thermostat or PCB Board

If the thermostat sensor or printed circuit board (PCB) is faulty, the unit may not register the room temperature correctly and fail to cool properly. Fix: Component replacement — quoted on inspection.

Reason 6: Blocked Outdoor Condenser Unit

If your outdoor condenser unit is blocked by vegetation, furniture, or debris, heat cannot dissipate effectively. Fix: Clear the area around the unit (minimum 30cm clearance on all sides).

Reason 7: Aircon Fan Speed Set Too Low

Low fan speed means less air is being cooled and circulated. Try setting the fan to high first before calling for service.

When Should You Call a Professional?

Call Alpha & Omega Trinity if:

• Cleaning the filter doesn't help within 1 hour
• You see ice forming on the indoor or outdoor unit
• The unit makes unusual noises (banging, hissing, squealing)
• Water is leaking from the indoor unit
• The aircon trips the circuit breaker repeatedly

Book Aircon Service Today

📞 6816 2462 | 💬 WhatsApp: +65 8400 6354
🌐 www.aot.com.sg | Same-day service available across Singapore.