Why Is My Aircond Not Cooling in Malaysia — 5 Causes and What to Fix First
You switch on your aircond. The fan is running. The light is on. But the room stays warm — or barely gets cool even after 30 minutes.
If this sounds familiar, you are not alone. This is the single most common aircond complaint across Malaysia every week. The good news is that in most cases, the problem is fixable — and sometimes you can solve it yourself without spending a single ringgit.
In this guide we walk through the 5 most common reasons an aircond stops cooling in Malaysia, what each problem means, how serious it is, and exactly what you should do next. We will start with the simplest checks and work up to the more serious faults.
Before You Call Anyone — Check These 3 Things First
Before assuming something is broken, spend 5 minutes checking the basics. You would be surprised how often one of these is the real problem.
✅ Quick 3-Point Check
If all three check out and the room is still warm — one of the five causes below is responsible.
The 5 Real Reasons Your Aircond Is Not Cooling
This is the most common cause — and the easiest fix. Your aircond pulls warm room air through a filter before cooling it. When that filter gets packed with dust, pet hair, and dirt, almost no air can pass through. The unit runs, but barely any cool air comes out.
In Malaysia's dusty environment, filters can clog surprisingly fast — especially if you live near a main road, have pets, or use your aircond daily. Most people check their filter far less often than they should.
How to check it: Open the front panel of the indoor unit (it usually clips open). Pull out the filter. If it looks grey, dark brown, or is visibly packed with dust — that is your problem.
How to fix it: Wash the filter under a tap with clean water. Let it dry completely — do not put it back wet. Refit it and test. This takes 10 minutes and costs nothing. If cooling improves immediately, the filter was your problem.
- Very weak airflow even on the highest fan speed
- Unit has been running for months without any service
- Dusty smell when the unit turns on
- Unit runs continuously without cooling the room
Refrigerant gas — sometimes called Freon — is the chemical inside your aircond that actually absorbs heat from the room and releases it outside. Without enough gas, your unit simply cannot cool properly no matter how long it runs.
Here is the important thing most people do not know: refrigerant gas does not get used up like petrol. If your gas is low, it means there is a leak somewhere in the system. Topping up the gas without finding and fixing the leak first is a temporary patch — the gas will run out again within weeks.
This is one of the most common problems we see across Shah Alam and the surrounding areas — particularly in older units where the copper piping has started to corrode or where the original installation used poor quality fittings.
What to do: Call a certified technician to do a gas pressure test. They will check the pressure, find the leak, seal it properly, and then refill the gas to the correct level. Do not attempt to refill gas yourself — it requires proper tools, certified training, and handling of pressurised refrigerant.
- Air from the unit is barely cool or completely warm
- Ice forming on the copper pipes or indoor unit
- A faint hissing or bubbling sound from the unit
- TNB electricity bill suddenly higher than usual
🔍 Suspect a gas leak? Get a proper pressure test and written quote before any work starts.
Book Aircond RepairEven when your filter looks clean, the evaporator coil sitting behind it can be caked in mould, bacteria, and black grime. In Malaysia's year-round humidity, this build-up happens faster than in almost any other country in the world.
The evaporator coil is the part that actually absorbs heat from your room air. When it is coated in a thick layer of mould and dirt, it cannot absorb heat efficiently. The unit works hard, uses more electricity, but the room stays warm.
This is also the cause of that musty or mouldy smell many Malaysians notice when they first turn on their aircond. The smell is mould spores being pushed directly into your room air. It is not a cosmetic problem — it affects your air quality and should be dealt with quickly.
The fix for dirty coils is a professional aircond chemical wash — a deep cleaning service that uses safe chemical solutions to dissolve the mould and grime from inside the coils and blower wheel. A normal service wipes the surface. A chemical wash cleans what you cannot see.
For residents in Puchong and other densely populated condo areas, we recommend a chemical wash every 6 months due to the enclosed spaces and high humidity that accelerate mould growth inside indoor units.
- Musty or mouldy smell every time the unit runs
- Unit has not had a service in over 12 months
- Weak cooling despite a clean filter
- Ice forming on the indoor unit
Most people focus entirely on the indoor unit and forget the outdoor unit completely. But your outdoor unit does half the work — it releases all the heat that was absorbed from your room to the outside air. If it cannot do that, your aircond cannot cool.
There are two common problems. The first is physical blockage — plants, a fence, outdoor furniture, or stored items placed too close to the outdoor unit. Heat cannot escape and the unit overheats. The second is a dirty condenser — dust and debris coat the outdoor fins like a blanket, trapping heat inside.
This is a particularly common problem in Malaysia during peak afternoon hours — between 1pm and 4pm when outdoor temperatures hit 33 to 37 degrees. If your aircond cools well in the morning but struggles in the afternoon, a blocked or overheating outdoor unit is almost certainly the cause.
What to check: Walk outside and look at your outdoor unit. Make sure there is at least 30cm of clear space all around it. If it is dusty or clogged with debris, that needs cleaning. If it is in direct afternoon sunlight with no shade — that is making things worse.
- Aircond cools fine in the morning but not in the afternoon
- Outdoor unit feels unusually hot to the touch
- Plants, boxes, or furniture close to the outdoor unit
- Loud humming or rattling from the outdoor unit
This is the cause most people never suspect — because the unit seems to be working fine. But if your aircond is too small for the room it is trying to cool, it will run continuously without ever reaching your set temperature.
Aircond units are rated in horsepower (HP). A 1.0HP unit is designed for rooms up to about 150 square feet. A 1.5HP unit handles 150 to 250 square feet. A 2.0HP handles 250 to 400 square feet. If your unit is undersized, it will work at maximum capacity all day long — cooling poorly, using lots of electricity, and wearing out faster than it should.
In Malaysia, this problem is made worse by two factors: poor original installation advice, and rooms with high ceilings, west-facing windows, or heat-absorbing tile floors that require more cooling power than the basic room size calculation suggests.
What to do: Measure your room and compare it to the HP guide above. If your unit is clearly undersized, you have two options — replace it with a higher HP model, or add a second unit. A certified technician can advise you on the most cost-effective solution for your specific room.
- Unit runs non-stop but room never gets properly cold
- Always running at maximum fan speed and minimum temperature
- TNB bill is high but room comfort is still poor
- Larger rooms in the house cool fine but this one never does
Still not sure what is causing the problem?
Our JKKP-certified technicians diagnose accurately on the first visit — using gas pressure gauges, infrared scanners, and camera drain scopes. Written price before any work starts. 30-day warranty when we finish.
What Does It Cost to Fix an Aircond That Is Not Cooling in Malaysia?
Cost depends entirely on the cause. Here is an honest overview of what each fix typically costs in Malaysia in 2026.
| Problem | Typical Fix | Estimated Cost |
|---|---|---|
| Dirty filter | Self-clean at home | Free |
| Dirty coils or blower | Standard service | From RM99 |
| Mould inside unit | Chemical wash | From RM150 |
| Low refrigerant gas | Leak fix + gas refill | RM80 – RM250 |
| Blocked outdoor unit | Clean + clear space | Partially free |
| Faulty capacitor | Part replacement | RM80 – RM200 |
| Compressor fault | Repair or replacement | RM600 – RM1,200 |
| Undersized unit | Upgrade or add unit | From RM250 install |
The golden rule: always get a written price before any technician starts work. A reputable service will always do this — a verbal quote that changes after the job is a red flag.
When to Call a Technician Immediately
Some problems you can check yourself. Others need a trained person with the right tools. Call a certified aircond technician right away if you notice any of these:
- Unit is blowing warm air after you have checked the filter, remote settings, and outdoor unit
- Ice forming on the pipes or indoor unit panel
- The unit keeps tripping your fuse box or main switch
- You can smell burning or electrical smell from the unit
- Strange noises — grinding, banging, or continuous clicking
- Water dripping from the indoor unit onto your floor or ceiling
How to Prevent Your Aircond from Stopping to Cool in the Future
Prevention is always cheaper than repair. Here is the simple maintenance routine that keeps Malaysian aircond units running cold all year round.
Every 2 to 4 weeks: Clean your filter. Open the front panel, remove the filter, rinse under the tap, dry fully, refit. This single habit prevents the most common cooling problem and costs nothing.
Every 3 to 4 months: Book a standard aircond service. A trained technician will clean the blower wheel and coils, check gas pressure, flush the drain pipe, and test cooling performance. For daily users in Malaysia's climate, this schedule keeps your unit running efficiently and your TNB bill under control.
Every 12 months (or 6 months for condo units): Book a chemical wash. This removes the deep mould and grime build-up that a regular service cannot reach. It is the single most effective thing you can do to maintain air quality and prevent the cooling efficiency from dropping over time.
📅 Ready to book a service? Same-day slots available across KL and Selangor.
WhatsApp ACFix NowFrequently Asked Questions
Why is my aircond running but not cooling the room?
The most common reasons are low refrigerant gas due to a leak, a dirty or clogged air filter, dirty evaporator coils covered in mould and grime, a blocked outdoor unit that cannot release heat, or a faulty compressor. In Malaysia, dirty coils and low gas are by far the most frequent causes. Check your filter first — if it is grey and packed with dust, clean it and test again before calling a technician.
How do I know if my aircond gas is low?
Signs of low refrigerant gas include the unit running continuously without cooling the room, ice forming on the copper pipes or indoor unit, a hissing or bubbling sound from the unit, and a higher electricity bill than usual. Low gas almost always means there is a leak somewhere in the system. Topping up gas without fixing the leak is a waste of money — the gas will run out again within weeks or months.
Can I fix my aircond not cooling problem myself?
Yes, for some causes. Cleaning a dirty filter takes 10 minutes and costs nothing. Clearing space around a blocked outdoor unit is also a DIY fix. However, refrigerant gas issues, dirty internal coils, and compressor problems all require a trained and certified technician with proper tools. Do not attempt to open the electrical components or handle refrigerant gas yourself.
How much does it cost to fix an aircond that is not cooling in Malaysia?
It depends on the cause. A standard service to clean coils and flush the drain costs from RM99. A chemical wash to deep-clean mould from inside the unit starts from RM150. A gas refill starts from RM80 depending on gas type. A repair diagnostic is typically RM88 and covers identifying the fault with a written quote before any work starts. Compressor replacement is the most expensive fix — RM600 to RM1,200 depending on brand and HP.
Why does my aircond work at night but not during the day?
This is a classic sign of a blocked or overheating outdoor unit. During the day, outdoor temperatures in Malaysia can reach 33 to 37 degrees. If the outdoor unit is in direct sunlight or poorly ventilated, it overheats and reduces cooling capacity dramatically. At night when temperatures drop, the unit recovers and cools normally. Check that the outdoor unit has at least 30cm of clear space around it and is not in direct afternoon sunlight.
How long should I wait for my aircond to cool the room?
A properly working aircond should noticeably cool the room within 10 to 15 minutes of switching on. A large room above 250 square feet may take 20 to 25 minutes to reach the set temperature. If the room is still warm after 30 minutes of running — something is wrong and you should check the filter, outdoor unit, and set temperature before calling a technician.
Need a certified aircond technician in KL or Selangor?
ACFix.my covers Shah Alam, Puchong, Petaling Jaya, Klang, and all surrounding areas. JKKP-certified technicians. Written price before every job. Same-day slots available.
Written by the ACFix.my technical team — JKKP-certified aircond technicians who service, repair, and install all major brands across KL and Selangor every week. All causes, symptoms, and cost estimates in this article are based on real service experience, not manufacturer claims. Last reviewed and updated: May 2026.
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