Why Is My Aircon Not Cold? 7 Causes and Fixes for Singapore Homes

If your aircon is running but your room still feels warm, you’re not alone. In Singapore, where the aircon runs almost daily, this is one of the most common complaints.

Let’s break down 7 likely reasons your aircon is not cold and how to fix them. Whether it’s a clogged filter or a bigger issue like low gas, this guide helps you troubleshoot before calling for help.

What causes aircon leaks? This graphic highlights the top five reasons your unit may be dripping water, with simple explanations for Singapore homeowners.

1. Clogged Air Filters

Dust and dirt block airflow and make your aircon work harder. Over time, it cools less and uses more electricity.

Fix: Clean your filters every 3–4 weeks if you use your aircon often. If airflow is still weak, schedule a basic servicing.

2. Low Refrigerant Gas (R32 or R410A)

If your aircon runs but isn’t cold, it could be low on gas. This means it can’t remove heat from the room effectively.

Fix: Call a licensed technician to check the gas pressure and top it up. In Singapore, we commonly use R32 or R410A. If the gas is low again within months, there might be a leak.

3. Dirty Indoor or Outdoor Coils

When coils are coated in dust or grime, they can’t transfer heat properly. This reduces cooling and may cause ice to form on the unit.

Fix: You may need a chemical cleaning to remove the dirt from the coils. Basic servicing won’t be enough once the buildup is thick.

4. Faulty Thermostat

Sometimes, the thermostat doesn’t read the room temperature correctly or shuts off too early.

Fix: Try setting your thermostat to 22°C. If the aircon still isn’t cold, the sensor might be faulty. A technician can replace or reposition it.

5. Gas Leaks in the System

If the refrigerant is leaking, your system slowly loses its cooling ability. This also causes long-term damage to your compressor.

Fix: Get a technician to do a leak test. At Sky Blue Aircon Engineering, we inspect copper piping and joints before any refill.

6. Blocked Drainage

Water buildup in the drain tray can cause the aircon to shut down or reduce airflow. This leads to weak cooling and sometimes leaking.

Fix: During servicing, the drainage system is vacuumed or flushed to prevent clogging. Don’t ignore dripping — it often leads to this issue.

7. Old or Failing Compressor

If your aircon is more than 8–10 years old and not cooling, the compressor might be worn out.

Fix: Replacement is likely needed. Before replacing, always check if it’s just a gas or coil issue — this could save you hundreds.

FAQ

Q1: Why is my aircon not cold even after cleaning the filter?

It could be a gas issue, dirty coils, or a failing part like the compressor.

Q2: How do I know if my aircon has a gas leak?

Cooling becomes weaker over time and doesn’t recover even after servicing.

Q3: Is chemical cleaning always required?

No, only if basic cleaning doesn’t restore cooling. It’s usually done once every 12–18 months.

Q4: How often should I service my aircon in Singapore?

Every 3 to 4 months for daily use. Less often if you only use it occasionally.

Q5: Can I fix this myself?

You can clean the filter, but gas checks and internal repairs should be done by a technician.

Is your aircon still not cooling? Contact Sky Blue Aircon Engineering for a proper inspection and honest diagnosis.