The Most Common Air Conditioning Problems and How to Fix Them

Air conditioning issues are frustrating, especially when they happen at the worst possible time. But the good news is that many common problems of air conditioners are preventable or easily fixable. Whether your AC is leaking, making strange noises, or refusing to turn on, understanding aircon common problems can save you time, money, and discomfort.

At Lenergy, we know how important a well-functioning aircon is for your home or business. In this guide, you’ll learn the most common air conditioning problems, along with other frequent issues and how to fix them. By the end, you’ll know whether you can troubleshoot the issue yourself or if it’s time to call a professional.

Most Common Aircon Problems and How to Fix Them

Air conditioners are complex machines, and when something goes wrong, it can be frustrating. Below are some of the most common aircon problems and what you can do about them.

1. Weak or No Cooling

One of the most common aircon problems is when your unit runs but doesn’t cool properly. You might feel weak airflow or warm air coming out of the vents.

Possible Causes & Fixes:

• Dirty air filters – A clogged filter blocks airflow. Check and replace your air filter. 
• Low refrigerant levels – If your AC is low on refrigerant, there may be a leak. You’ll need a professional to inspect and refill it.
• Blocked condenser unit – If the outdoor unit is dirty or covered by debris, clean it to improve airflow.
• Controller issues – Make sure the controller is set to cooling mode and at the right temperature.

2. Air Conditioner Leaking Water

Noticing water dripping from your AC unit? Leaks can cause water damage and indicate a bigger problem.

Possible Causes & Fixes:

• Clogged drain line – Dirt and mould can block the drain pipe. Try using a wet/dry vacuum to clear it.
• Frozen evaporator coils – If ice builds up on the coils, turn off the unit and let it defrost. This usually happens due to restricted airflow.
• Low refrigerant – Low refrigerant levels can also cause coils to freeze. A technician can check for leaks and refill the refrigerant.

3. Strange Noises Coming from Your AC

Air conditioners aren’t silent, but loud or unusual noises can signal an issue.

What Different Sounds Mean:

• Banging or rattling – Loose parts inside the unit may need tightening.
• Buzzing or humming – Could indicate an electrical issue or a failing motor.
• Squealing – Often caused by worn-out components or a motor problem.

If your AC is making unusual noises, turn it off and inspect the unit. If the noise persists, call a technician.

4. Bad Odours from the Air Conditioner

The Problem: If your AC smells musty or burnt, there could be an issue inside the system.

Possible Causes & Fixes:

• Mould or mildew – A damp AC can become a breeding ground for mould. Clean or replace filters and check for standing water.
• Burning smell – Could be a sign of electrical issues. Turn off the unit and call a professional.

5. Aircon Not Turning On

The Problem: Your AC won’t power up, no matter what you try.

Possible Causes & Fixes:

• Tripped circuit breaker – Check your home’s electrical panel and reset the breaker if needed.
• Dead controller batteries – Replace the batteries and try again.
• Blown fuse – Fuses can burn out and need replacing.

6. High Energy Bills

The Problem: If your electricity bill has suddenly spiked, your AC may be running inefficiently.

Possible Causes & Fixes:

• Dirty filters – Restricted airflow makes your unit work harder. Replace the filters regularly.
• Old or inefficient AC unit – If your AC is over 10–15 years old, it may be time for an upgrade.
• Poor maintenance – Regular servicing helps keep your system running efficiently.

7. Short Cycling (AC Turning On and Off Quickly)

The Problem: Your AC turns on, runs for a short time, then shuts off before cooling properly.

Possible Causes & Fixes:

• Dirty filters or coils – A clogged system can overheat and shut down. Clean or replace filters.
• Oversized AC unit – If your aircon is too powerful for the space, it will cool too quickly and shut off. In this case, you may need a better-sized unit.

These are some of the most common aircon problems and how to fix them. If you’ve checked these issues and your AC still isn’t working properly, it may be time to call a professional.

When to Call a Professional

While some aircon common problems can be fixed with basic troubleshooting, others require expert attention. Ignoring serious issues could lead to bigger (and more expensive) repairs. Here are some signs that it’s time to call in a professional:

1. Your AC Still Isn’t Cooling Properly

If you’ve cleaned the filters, checked the controller, and ensured the outdoor unit is clear, but your AC still isn’t cooling, you may have a refrigerant leak or a failing compressor—both of which need expert repair.

2. There’s a Persistent Water Leak

Occasional condensation is normal, but if your AC is leaking water inside your home or pooling around the unit, it could indicate:

• A blocked or damaged drainage system
• Frozen evaporator coils
• A cracked or overflowing drain pan

These issues need professional servicing to prevent further damage.

3. Your AC Is Making Loud or Strange Noises

Some noises, like a quiet hum, are normal. However, if you hear:

• Grinding or screeching – Your AC’s motor bearings may be failing.
• Banging or rattling – Loose parts inside the unit need to be repaired.
• Clicking that won’t stop – This could indicate an electrical problem.

Unusual sounds should never be ignored, as they can lead to more serious damage.

4. Your Energy Bills Are Unusually High

If your electricity bill has spiked but your usage hasn’t changed, your AC may be running inefficiently due to:

• A failing motor or compressor
• Low refrigerant levels
• Poor system maintenance

A professional can diagnose the issue and recommend solutions to restore efficiency.

5. Your AC Frequently Turns On and Off (Short Cycling)

If your AC short cycles, it might be overheating, have a faulty controller, or be improperly sized for your home. A technician can identify the cause and prevent unnecessary wear and tear on your unit.

6. There’s a Burning or Electrical Smell

If your AC smells like something is burning, turn it off immediately. This could be caused by:

• Overheated wiring
• A failing motor
• Electrical issues that could pose a fire hazard

Call a technician right away to inspect and fix the problem.

If you notice any of these warning signs, don’t wait for the problem to get worse. A professional technician can help extend the life of your AC and keep your home comfortable.

Need Help With Your Aircon?

Air conditioners are essential for keeping your home comfortable, but like any appliance, they can develop issues over time. The good news is that many common aircon problems can be prevented or fixed with regular ac maintenance and simple troubleshooting.

By cleaning filters, checking the controller, and keeping the outdoor unit clear, you can often solve minor issues yourself. However, if your AC continues to struggle, makes loud noises, leaks excessively, or causes your energy bills to spike, it’s best to call a professional.

At Lenergy, we understand how frustrating aircon issues can be. That’s why regular servicing and early problem detection are the best ways to avoid costly repairs and keep your AC running efficiently.Need expert help with your air conditioner? Contact Lenergy today for professional servicing and repairs.