If your aircon is running but not cooling well, making strange sounds, or turning on and off by itself, the problem could be in two major parts: the capacitor or the compressor. These components play a big role in keeping your aircon cooling efficiently. When either one becomes faulty, your aircon will struggle — or may stop working completely.
Understanding early warning signs can help you avoid sudden breakdowns, high repair costs, and rising electricity bills, especially in Singapore’s hot and humid climate.
What Does the Capacitor Do?
The aircon capacitor acts like a battery. It gives the compressor and fan motor the boost they need to start and run smoothly.
Signs of a Faulty Capacitor:
Aircon hums but doesn’t start
Weak or inconsistent airflow
Unit takes long to cool the room
Aircon turns off by itself
A burning smell from the indoor or outdoor unit
Important: A faulty capacitor is one of the most common issues seen in aircon repair in Singapore. It is also relatively affordable to replace — as long as it’s caught early.
What Does the Compressor Do?
The compressor is the heart of your aircon. It pumps refrigerant (gas) through the system to absorb heat and cool your room.
Signs of a Faulty Compressor:
Aircon is running but not cooling at all
Unusual loud buzzing or rattling noises
Frequent tripping of the circuit breaker
Very high electricity bills
Aircon only blows warm air
A failing compressor is more serious. In many cases, repairing or replacing the compressor can be expensive. Therefore, catching the problem early can help save your aircon from total failure.
Capacitor vs. Compressor Issues: How to Tell the Difference
It can be hard to tell if your aircon problem comes from the capacitor or the compressor, since their symptoms can look quite similar. But there are clear signs to help you figure it out.
If your aircon hums when starting, turns off by itself, or blows weak air, it’s likely a capacitor issue. The good news is that this problem is usually simple and affordable to fix — especially if you catch it early.
On the other hand, if your aircon runs but doesn’t blow cold air, or if the outdoor unit makes loud buzzing sounds, the compressor may be the problem. You might also notice your power trips when turning the aircon on. That’s a warning sign of compressor overload.
In short:
Capacitor problems affect how the aircon starts.
Compressor problems affect how well it cools.
Tip: If your aircon is more than 8–10 years old, replacing the compressor may not be worth the cost. It may be cheaper to replace the entire unit.
What You Should Do Next
Instead of guessing, the safest step is to schedule a professional aircon inspection. A trained technician can test both the capacitor and compressor quickly using proper tools.
Do not try to fix these parts yourself. Both components involve electrical current and pressurised refrigerant — which can be dangerous to handle without training.
How Lion City Air Conditioner Services Can Help
At Lion City Air Conditioner Services, we provide:
Aircon troubleshooting and diagnosis
Capacitor replacement
Compressor fault testing and repairs
Aircon gas top-up
General servicing and chemical wash
We help you restore cooling, improve efficiency, and extend the life of your system — without unnecessary replacements.
📞 Call us at +65 8818 5781
🌐 Or book online at https://lioncityaircon.sg
