Aircond Not Cold? 7 Common Causes & Fixes

Why Is My Aircond Not Cold? 7 Common Reasons

It feels like the heat in Kuala Lumpur gets more intense every year. You walk into your home, grab the remote, and wait for that blast of cool air, but all you get is a lukewarm breeze. It is frustrating, especially when you just want to relax after a long day in Kepong’s traffic.

We see this scenario daily. Most homeowners assume the unit is broken and needs a costly replacement, but that is rarely the case. From our experience, the issue is usually a maintenance oversight that is choking your system’s efficiency. A 2025 report indicates that a dirty air conditioner can increase your electricity usage by up to 25%, which directly impacts your monthly TNB bill.

Let’s look at the data, what your unit is trying to tell you, and how to fix these common cooling issues. Here are the 7 reasons your aircond isn’t doing its job.

Reason 1: Dirty Air Filters

Likelihood: Very High

This is the single most common reason for a sudden drop in cooling performance. It is also the easiest problem to solve on your own.

Why it happens Your air conditioner breathes in air from your room to cool it. When the filters are clogged with dust, hair, and pollutants, the system suffocates. This restriction drops the airflow over the evaporator coil. Without enough warm air passing over the cold coil, the system cannot remove heat effectively.

The “So What” for homeowners Ignoring this does not just make you sweat. It forces your unit to run longer cycles to reach the set temperature. This extra strain is a primary driver of those spiking electricity bills we mentioned earlier.

Fix it yourself

Turn off the wall switch for safety.
Open the front panel and gently slide out the mesh filters.
Wash them with water and a mild soap if they are greasy.
Let them dry completely in a shaded area.
Slide them back in and close the panel.

Insider Tip: In Kepong and KL, we deal with high pollution and construction dust. While manuals say to clean filters monthly, we recommend doing it every two weeks during hazy seasons or if you live near a main road.

Reason 2: Low Refrigerant (Gas)

Likelihood: High

Refrigerant is the chemical fluid that absorbs heat from your room and releases it outside. Whether your unit uses the older R410A or the newer, more efficient R32 gas, low levels mean zero cooling.

Why it happens There is a common myth that gas gets “used up” like petrol in a car. That is incorrect. Your air conditioner is a closed-loop system. If the gas is low, it means there is a leak in the copper piping or fittings.

Signs of low gas

The unit runs, but the air feels like a fan.
You see ice forming on the copper pipes at the outdoor unit.
There is a faint hissing sound coming from the indoor unit.
Your electricity bill jumps because the compressor never stops running.

Can you fix it? No. This requires professional tools to find the leak, repair it, and refill the gas to the precise pressure. We check for leaks during our inspection because simply topping up the gas without fixing the leak is a waste of your money.

Cost: RM80-150 for a gas top-up. Our team includes a gas check with every chemical wash service.

Reason 3: Dirty Evaporator Coil & “Aircond Jelly”

Likelihood: High

The evaporator coil is the cold radiator inside your indoor unit. If the filters are the mask, the coil is the lungs. When it gets blocked, the heat exchange stops.

Why it happens Even with clean filters, microscopic dust eventually settles on the wet coil. In Malaysia’s humid climate, this creates a perfect breeding ground for bacteria and mold. This mixture forms a thick, slimy substance known in the industry as “Aircond Jelly.”

Signs

Cooling power has gradually declined over the last 3-6 months.
The airflow feels weak even on the highest fan setting.
You smell a musty, sour odor when the unit first turns on.
Water starts leaking from the unit because the jelly has clogged the drainage tray.

Fix A standard service often isn’t enough to remove this bio-slime. We recommend a chemical wash (sometimes called a chemical overhaul) to dissolve the buildup and flush out the jelly. This restores the coil’s ability to transfer heat and can improve cooling efficiency by up to 30%.

Reason 4: Thermostat & Setting Issues

Likelihood: Medium

Sometimes the hardware is fine, but the instructions it is receiving are wrong. We have arrived at many homes to find the unit in the wrong mode.

Check these settings

Mode Selection: Ensure the remote shows a “Snowflake” icon (Cool Mode). If you see a “Water Drop” icon, it is in Dry Mode, which prioritizes humidity removal over cooling.
Fan Speed: If it is set to “Auto” or “Low,” the air might not circulate far enough to cool the room.
Batteries: Old batteries can leak and cause the remote to send weak or erratic signals.

Try this Set the temperature to 16°C and the fan to high. Wait 10 minutes. If the room starts getting cold, the issue might be your thermostat sensor needing calibration rather than a mechanical failure.

Reason 5: Blocked Condenser Unit (Outdoor Unit)

Likelihood: Medium

The outdoor unit (condenser) has one job. It dumps the heat taken from your room into the outside air. If it cannot breathe, that heat stays in your house.

Why it happens This is common in condos around KL where units are placed in tight balcony nooks. We also see units choked by dried leaves, pigeon nests, or items stacked in front of the fan.

Check

Is there at least 2 feet of clear space in front of the fan?
Are the thin metal fins on the back clogged with dirt?
Is the fan spinning fast when the AC is on?

Fix it yourself

Clear away any boxes, flower pots, or debris.
Use a garden hose with low pressure to gently rinse the dust off the back fins.
Warning: Do not use a high-pressure jet, as you will bend the delicate fins and ruin the unit.

Reason 6: Frozen Evaporator Coil

Likelihood: Medium

It sounds contradictory, but your AC can stop cooling because it is literally freezing. A block of ice on the coil acts like a wall, stopping air from passing through.

Why it happens Ice forms when the coil gets too cold because there isn’t enough warm air blowing over it (dirty filters) or the pressure is too low (low gas).

Signs

Visible white frost or ice on the indoor fins.
The unit spits out water droplets or mist.
You hear a cracking sound as the plastic expands and contracts.

Fix it yourself

Turn off the cooling mode but leave the fan running.
Let it thaw for 2-4 hours. You might need to put towels down to catch the melting water.
Check your filters immediately.

Insider Tip: If the ice comes back after you clean the filters, you likely have a refrigerant leak. You will need a professional to assess the pressure levels.

Reason 7: Compressor or Capacitor Failure

Likelihood: Low (but serious)

The compressor is the heart of the system. If it stops pumping, the cooling stops instantly. However, the problem is often a small, cheap part attached to it.

The Capacitor Factor Before you fear the worst, know that the capacitor is a small cylinder that kickstarts the compressor. It fails frequently due to power fluctuations, which are not uncommon during storms in Malaysia. If the capacitor is dead, the compressor tries to start but can’t.

Signs

The indoor unit runs, but the outdoor unit is silent.
You hear a loud “clicking” or buzzing sound from outside every few minutes.
The circuit breaker trips immediately when you turn on the AC.

Can you fix it? This is strictly a job for a professional AC repair technician due to the high voltage involved. A capacitor replacement is affordable (around RM150-200), whereas a full compressor replacement can cost RM800-2000. We always check the capacitor first to save you money.

Quick Diagnosis Flowchart

Step 1: Is air blowing from the indoor unit?

No → Check the remote batteries and your home’s circuit breaker.
Yes → Continue to Step 2.

Step 2: Is the air cold or just room temperature?

Room Temp → Go to Step 3.
Cold but weak airflow → Check Reason 1 (Filters) or Reason 3 (Coil).

Step 3: Is the outdoor unit fan spinning?

No → Possible electrical issue or dead capacitor. Call a pro.
Yes → Continue to Step 4.

Step 4: Do you see ice on the pipes or indoor unit?

Yes → Turn it off immediately. You likely have low gas or a dirty coil.
No → Check your temperature settings again.

What You Can Fix vs. What Needs a Pro

Issue	Difficulty	Can I DIY?
Dirty filters	Easy	✅ Yes
Wrong settings	Easy	✅ Yes
Blocked outdoor unit	Easy	✅ Yes
Frozen coil (thawing)	Easy	✅ Yes
Low refrigerant (Gas)	Hard	❌ No (Requires license)
Aircond Jelly (Chemical Wash)	Hard	❌ No (Requires equipment)
Dead Capacitor	Hard	❌ No (High Voltage Risk)
Compressor Failure	Hard	❌ No (Complex repair)

Prevention Tips

Clean filters every 2 weeks: Set a recurring reminder on your phone.
Schedule a chemical wash annually: This prevents the “jelly” buildup that causes leaks and poor cooling.
Keep the outdoor area clear: Ensure your balcony or yard doesn’t get cluttered around the unit.
Monitor your electricity bill: A sudden RM50-100 increase is often the first silent alarm of a dirty AC.

Cost Comparison

We believe in transparency. Here is what you can expect to pay for standard services in the KL/Kepong market for 2025.

Solution	Est. Cost	What it fixes
Filter cleaning	Free	Basic airflow issues
Gas top-up	RM80-150	Leaks & low cooling power
Capacitor Change	RM150-200	Outdoor unit not starting
Chemical wash	RM130-250	Deep clean for “jelly” & mold
Compressor repair	RM800-2000+	Major system breakdown

Smart spending: Spending RM150 on a chemical wash once a year is much cheaper than paying an extra RM50 every month on electricity bills due to a dirty, inefficient unit.

Still not cold after troubleshooting? Contact AC Service Pro at 012-2252 623. We’ll diagnose the problem and get your aircond cooling again - same-day service available in Kepong.