Posted on Oct 15, 2026 by letscool Aircon

Aircon Repair

In Singapore’s hot and humid climate, a properly functioning air conditioning system is essential for maintaining a comfortable indoor environment. However, many homeowners experience a common problem: one room feels cool and comfortable, while another remains warm even when the aircon is running. This situation can be frustrating, especially in HDB flats, condominiums, and landed properties with multiple indoor air conditioning units.

If you are wondering, “Why is my aircon cooling one room but not another?”, several factors could be responsible, including dirty filters, blocked airflow, thermostat settings, refrigerant problems, or faulty components. Understanding these causes can help you identify the right solution and decide when professional assistance is necessary.

LetsCool Aircon provides professional aircon servicing Singapore residents can rely on to maintain cooling performance, improve airflow, and identify potential air conditioning problems.

1. Dirty Aircon Filters and Blocked Airflow

One of the most common reasons an aircon cools one room but not another is restricted airflow. Dust, dirt, and other particles can accumulate inside the air filters, reducing the amount of cool air delivered into the room. When airflow becomes restricted, the aircon may take longer to cool the space or struggle to reach the desired temperature.

This problem is particularly noticeable in rooms where the air conditioning units have not received regular maintenance.

Common signs of restricted airflow include:

• Weak airflow from the indoor unit.

• One room taking longer to cool than others.

• Dust accumulating around the aircon vents.

• Unusual smells when switching on the unit.

• The aircon running continuously without cooling effectively.

Cleaning the air filters regularly can help restore airflow. However, if the filters are clean but the problem continues, dirt may have accumulated on the evaporator coil, blower fan, or other internal components.

Professional aircon general servicing helps remove accumulated dirt and allows technicians to inspect the system. Depending on the condition of the unit, an aircon chemical wash or aircon steam wash may be recommended to address heavier contamination.

For homeowners seeking the best aircon servicing Singapore has to offer, regular maintenance is an important step towards maintaining consistent cooling across multiple rooms.

2. Different Thermostat Settings and Room Conditions

Sometimes, the aircon itself is functioning correctly, but differences in room conditions prevent consistent cooling. Each room has its own cooling requirements depending on its size, sunlight exposure, window placement, insulation, and number of occupants.

For example, a bedroom facing direct afternoon sunlight may become warmer than another bedroom located on the shaded side of the property. Similarly, a room with several electronic devices may generate more heat than a room used mainly for sleeping.

Incorrect temperature settings can also contribute to uneven cooling. In multi-split air conditioning systems, individual indoor units may have different operating settings, depending on the system design.

Try these simple checks:

• Confirm that the affected room is set to cooling mode rather than fan mode.

• Check whether the temperature setting is appropriate.

• Make sure curtains or furniture are not blocking the airflow.

• Keep doors and windows closed while the aircon is operating.

• Check that the indoor unit's air outlet is unobstructed.

If the room remains warm despite correct settings, the aircon may be undersized for the space or experiencing a technical problem.

LetsCool Aircon can assess the room's cooling requirements and recommend suitable maintenance, aircon repair Singapore services, or aircon installation Singapore solutions when an existing system is no longer suitable.

View more: What is Chemical Cleaning? & Benefits of Aircon Chemical Wash 

3. Refrigerant Problems, Leaks, and Faulty Components

If one indoor unit is cooling properly while another produces warm air, the problem may involve the affected unit's refrigerant circuit, expansion device, sensors, or other components. The exact cause depends on whether your property uses a multi-split system or separate air conditioning systems.

A refrigerant leak can reduce cooling performance. Although people sometimes assume that an aircon needs an aircon gas topup whenever it stops cooling effectively, refrigerant does not normally get consumed during regular operation. If the refrigerant level is low, a technician should investigate the cause and repair any leak before recharging the system.

Other possible issues include a malfunctioning expansion valve, a faulty temperature sensor, damaged electrical connections, or a problem with the indoor unit's control board.

Watch for these warning signs:

• Aircon not cold: The affected room receives warm or insufficiently cooled air.

• Aircon water leakage: Water drips from the indoor unit because of drainage problems, ice formation, or other faults.

• Aircon light blinking: A flashing indicator may signal a fault that requires inspection.

• Aircon error code: The display may show a code indicating a particular system malfunction.

If these symptoms occur, avoid repeatedly restarting the unit or attempting electrical repairs yourself. Professional aircon repair Singapore services can help identify the underlying fault.

Depending on the diagnosis, the technician may recommend aircon spare parts replacement, aircon compressor servicing, sensor repairs, or other corrective work. An aircon chemical overhaul may also be appropriate when internal components require more extensive cleaning, but it will not resolve every mechanical or electrical fault.

4. When Should You Consider Aircon Servicing or a Chemical Wash?

Regular maintenance is essential for preventing uneven cooling and keeping multiple air conditioning units operating efficiently. Over time, dust, mould, and other contaminants can collect inside the cooling coils, blower fans, and drainage systems.

If one room consistently feels warmer than another, professional inspection can determine whether the issue is caused by dirt buildup, restricted airflow, or a component failure.

Different maintenance services address different problems:

• Aircon General Service: Suitable for routine cleaning, filter maintenance, drainage checks, and general performance inspection.

• Aircon chemical wash: Helps remove stubborn dirt and buildup from internal cooling components when routine servicing is insufficient.

• Aircon steam wash: Uses steam-based cleaning methods to help remove accumulated grime from suitable components.

• Aircon chemical overhaul: Involves more extensive dismantling and cleaning when the unit's condition requires deeper maintenance.

• Aircon compressor servicing: Helps assess compressor-related performance problems, although not every cooling issue originates from the compressor.

The correct service depends on the unit's condition and the technician's findings. A chemical wash or overhaul should not be recommended automatically when the actual cause is a faulty sensor, refrigerant leak, or electrical issue.

Homeowners can also consider an aircon service contract to arrange regular maintenance visits throughout the year. Consistent servicing helps detect developing problems earlier and may reduce unexpected breakdowns.

LetsCool Aircon offers air conditioning maintenance and repair solutions for residential and commercial properties in Singapore, helping customers choose suitable services for their systems and usage requirements.

5. How to Prevent Uneven Cooling and When to Call a Professional

Preventing uneven room temperatures begins with regular maintenance and paying attention to changes in your aircon's performance. Small problems, such as dirty filters or blocked vents, can often be addressed before they develop into more serious cooling issues.

Follow these practical maintenance tips:

1. Clean the filters regularly. Check the manufacturer's instructions and clean reusable filters as recommended.

2. Schedule routine servicing. Arrange aircon general servicing based on usage, environmental conditions, and the manufacturer's guidance.

3. Keep indoor units unobstructed. Ensure curtains, cabinets, and other furniture do not block the air outlet.

4. Monitor unusual symptoms. Take note of water leakage, flashing indicator lights, error codes, or sudden changes in cooling performance.

5. Arrange professional inspections. If one room remains warm despite basic checks, have the system inspected before replacing parts unnecessarily.

You can also look out for an aircon promotion when planning routine maintenance or a new installation. Compare the service scope, pricing, and warranty conditions rather than choosing a package based on price alone.

If your current air conditioning system repeatedly struggles to cool certain rooms, a professional assessment can help determine whether repairs, maintenance, or aircon installation Singapore services would be the most practical long-term solution.

LetsCool Aircon helps homeowners identify common cooling problems and select appropriate maintenance or repair options. With professional attention and a suitable servicing schedule, you can maintain more consistent indoor comfort throughout Singapore's warm weather.

Conclusion

When your aircon cools one room but not another, the problem may be caused by dirty filters, blocked airflow, different room conditions, refrigerant leaks, or faulty components. Checking the settings and cleaning accessible filters are useful first steps, but persistent cooling problems require a proper inspection.

Routine aircon servicing Singapore homeowners can arrange helps maintain airflow and identify developing faults. Whether you need an Aircon General Service, aircon chemical wash, aircon chemical overhaul, aircon gas topup after leak repairs, or professional aircon repair Singapore support, choosing the correct solution is essential.

Contact LetsCool Aircon for professional air conditioning maintenance, troubleshooting, and repair services in Singapore. With the right diagnosis and regular care, you can enjoy more reliable cooling and a comfortable environment in every room.

Aircon servicing Singapore

11 Mandai Estate,

 #05-15 Eldix,

Singapore 729908

Mail ID: info@letscoolaircon.com.sg

Service -WhatsApp Call: +65 9862 3678  

Installation - WhatsApp  Call: +65 94507178

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