Aircon Not Cold
Is your aircon not cold even though it is running? This is a common problem in Singapore, where air conditioners are used regularly because of the hot and humid weather. The problem may come from an incorrect remote setting, dirty air filter, a blocked cooling coil, weak airflow or refrigerant leakage.
Some issues can be fixed with simple checks. Others require professional aircon troubleshooting and repair. This guide from Letscool Aircon explains the common causes and easy steps you can take.
Why Is My Aircon Running but Not Cold?
An air conditioner needs clean components, unrestricted airflow, sufficient refrigerant and properly working electrical parts to cool a room.
When your aircon is running but not cold, you may notice:
- Warm air from the indoor unit
- Weak airflow
- The room taking too long to cool
- Ice on the aircon or copper pipe
- Water leaking from the indoor unit
- The outdoor unit not operating
- Unusual noises or smells
Follow the steps below before contacting a technician.
1. Check Your Aircon Remote Settings
First, make sure the aircon is set to Cool Mode, usually shown by a snowflake symbol. Fan Mode only circulates room-temperature air without cooling it.
Set the temperature between 23°C and 25°C and select medium or high fan speed. Check whether Sleep Mode or a timer has been activated accidentally. After changing the settings, wait 15 to 20 minutes.
Setting the temperature to 16°C will not necessarily cool your room faster. It may only make the compressor operate longer and consume more electricity.
2. Clean the Air Filters
A dirty aircon filter restricts airflow and reduces cooling performance. It can also cause the cooling coil to freeze.
Switch off the aircon, open the front cover and remove the filters. Wash them gently with clean water and let them dry completely before reinstalling them.
If you use your aircon daily, clean the filters every two to four weeks. You should also arrange general aircon servicing every three to four months, depending on usage.
3. Close the Doors and Windows
Open doors and windows allow cold air to escape while warm and humid air enters. Your aircon must then work harder to maintain the selected temperature.
Keep the room closed while the aircon is running. Use curtains or blinds to reduce direct sunlight and make sure furniture does not block the indoor unit’s airflow.
If the room becomes cold at night but remains warm during the day, strong sunlight, poor insulation or insufficient aircon capacity may be responsible.
4. Check for Weak Airflow
Place your hand near the indoor unit and check the airflow. If the air feels cold but the airflow is weak, the blower or cooling coil may be dirty.
Weak airflow can be caused by:
- Dirty filters
- A clogged cooling coil
- A dirty blower fan
- Ice inside the unit
- A faulty fan motor
If cleaning the filters does not improve the airflow, arrange professional aircon servicing in Singapore.
5. Look for Ice Formation
Ice on the indoor unit or copper pipe may be caused by restricted airflow, a dirty cooling coil, low refrigerant pressure or a faulty temperature sensor.
Switch off the aircon and allow the ice to melt naturally. Do not continue running a frozen unit because it may lead to water leakage or additional damage. Contact a technician if ice forms again.
6. Check the Outdoor Unit
The outdoor condenser releases heat from the room. If it is not working, the indoor unit may continue blowing air without producing effective cooling.
From a safe location, check whether the outdoor fan is running. Do not climb onto an aircon ledge or open the condenser yourself because it contains high-voltage electrical components.
If the outdoor unit is not operating or is making unusual noises, professional inspection is required.
7. Restart the Aircon Once
Switch off the aircon using the remote, turn off the power supply and wait approximately five minutes. Restore the power, select Cool Mode and set the temperature to 23°C or 24°C.
Restart the system only once. If it displays an error code or repeatedly trips the circuit breaker, contact an aircon repair company in Singapore.
Common Causes of an Aircon Not Cooling
Dirty cooling coil
Dust and mould can cover the cooling coil and reduce heat transfer. Light dirt may be removed through normal servicing. A heavily clogged coil may require an aircon chemical wash.
Low refrigerant or gas leakage
Refrigerant transfers heat between the indoor and outdoor units. Low pressure can cause poor cooling and ice formation.
Air conditioners do not normally consume refrigerant. A low level may indicate leakage from the piping, joints or cooling coil. The technician should inspect for leaks before performing an aircon gas top-up in Singapore.
Faulty thermistor or fan motor
A faulty thermistor may cause the aircon to stop cooling too early. A damaged fan motor can reduce airflow. These components should be tested and replaced by a qualified technician.
Compressor problem
The compressor circulates refrigerant through the system. If it fails, the indoor fan may run without producing cold air. A technician must determine whether repair or replacement is more economical.
Chemical Wash or Chemical Overhaul?
A chemical wash may be suitable for moderate dirt, mould and cooling problems. When the fan coil is severely clogged and requires extensive dismantling, an aircon chemical overhaul may be recommended.
Read our detailed guide about chemical wash vs chemical overhaul before choosing a service.
Chemical cleaning cannot repair refrigerant leaks, faulty motors, damaged circuit boards or compressor problems. An inspection is necessary to identify the correct solution.
Frequently Asked Questions
1. Why is my aircon running but not cold?
Your aircon may be running without cooling because of an incorrect remote setting, dirty air filter, clogged cooling coil, weak airflow, low refrigerant pressure or a faulty outdoor unit. Select Cool Mode, set the temperature between 23°C and 25°C and clean the filters. Contact a technician if the problem continues.
2. Why is my aircon not cold even after servicing?
If your aircon is not cold after servicing, the problem may be more serious than ordinary surface dirt. Possible causes include a deeply clogged cooling coil, dirty blower, refrigerant leak, faulty thermistor, weak fan motor, damaged control board or compressor problem.
3. Does an aircon that is not cold always need a gas top-up?
No. An aircon gas top-up is only required when testing confirms that the refrigerant pressure is low. Air conditioners do not normally consume refrigerant. A low level may indicate leakage from the piping, connection joints or cooling coil, which should be inspected before adding gas.
4. Can a dirty air filter cause the aircon not to cool?
Yes. A dirty air filter restricts airflow and reduces cooling performance. It may also cause ice to form on the cooling coil. Clean the filters every two to four weeks and arrange professional servicing every three to four months, depending on usage.
5. Why does my aircon become cold and then warm?
This may be caused by a frozen cooling coil, faulty temperature sensor, low refrigerant, overheating compressor or electrical problem. If the cooling changes repeatedly, arrange professional aircon troubleshooting to identify the cause.
6. Can a chemical wash fix an aircon that is not cold?
An aircon chemical wash may improve cooling when the coil, blower or drainage components are heavily clogged with dirt and mould. However, chemical cleaning cannot repair refrigerant leaks, faulty motors, damaged control boards or compressor problems.
7. How much does it cost to fix an aircon that is not cold in Singapore?
The cost depends on the actual problem and required service. General servicing normally costs less than chemical cleaning, gas-leak repair or major component replacement. Contact Letscool Aircon for an inspection and quotation before approving additional work.
Contact Letscool Aircon
If your aircon is not cooling, avoid repeatedly restarting it or requesting a gas top-up without diagnosis. Letscool Aircon provides professional aircon servicing, chemical cleaning, troubleshooting and repair across Singapore.