Aircon Not Cooling? 8 Reasons Your Singapore Aircon Is Not Cold (and How to Fix Each One)

If your aircon switches on, the fan runs, but the room stays warm, the problem is almost always one of eight things: a dirty filter, low gas, dirty coils, a weak compressor, a faulty thermostat, a drainage or piping issue, a unit that is the wrong size for the room, or plain old missed servicing. The good news: six of these are cheap to fix, and two of them you can often check yourself in under ten minutes.

This is our technician’s guide, written from what we see every day on HDB, condo and landed jobs across Singapore. Start with the two-minute self-check below. If the aircon is still not cold after that, call us on 9654 0044 or WhatsApp. Most repairs can be done the same day.

A 2-minute self-check before you call anyone

Before blaming the aircon, rule out these five quick ones. Most of the “aircon not cold” calls we get in Singapore actually come down to one of these.

1. Check the remote. Make sure the mode is set to Cool (the snowflake icon), not Fan or Dry. Set the temperature to 22 degrees.
2. Give it 10 minutes. A warm unit in a hot Singapore afternoon takes about 10 minutes to cool a room. Don’t judge it in 2 minutes.
3. Look at the filter. Open the front panel. If you can’t see through the mesh filter, that is your problem. Wash it under the tap.
4. Feel the outdoor unit. If the compressor (outdoor box) is silent when the indoor fan is running, the compressor is not kicking in. That needs a technician.
5. Check the breaker. Sometimes a tripped breaker in the DB box leaves the indoor fan running but kills the compressor.

If the unit is still not cold after this, read on. One of the 8 problems below is your answer.

1. Dirty or clogged air filters

The problem. In Singapore, the air is humid and dusty. The foam or mesh filters inside your indoor unit trap that dust. If you don’t wash them every few weeks, airflow drops. The fan is still running, but very little cold air is actually making it into the room.

Signs:

• Weak airflow at the vents, even on high fan speed
• More dust settling on your furniture than usual
• Higher than normal electricity bill
• The filter itself looks grey or brown when you take it out

What to do. Take the filter out, wash it under a tap with a soft brush, let it dry fully, then put it back. Do this every 2 to 4 weeks in Singapore if you run the aircon daily. Every 1 to 2 months is fine if you only use it at night.

If the filter is torn, warped or the dust has gone past the filter into the coil behind it, a general servicing will clean everything properly. Our general aircon servicing starts from $30 per unit and takes about 20 to 30 minutes per unit.

2. Low refrigerant gas (and sometimes a leak)

The problem. Refrigerant is the gas that actually does the cooling. Most new aircons in Singapore since 2018 run on R32 gas. Older units use R410A or R22. If the gas level is low, the unit will blow air but it will not be cold. Aircons are a closed system, so gas does not normally run out. If gas is low, there is almost always a small leak somewhere.

Signs:

• Aircon blows slightly cool for the first few minutes, then turns warm
• White frost or ice on the indoor copper pipes or the outdoor unit
• Hissing sound near the indoor or outdoor piping
• The unit has been “topped up” before and keeps losing cooling every few months

What to do. A proper fix is not just a gas top-up. A technician needs to pressure-test the system, find the leak, fix it, and only then refill the gas. If a company just tops up without finding the leak, you will be back to warm air in a few months and you will have paid twice.

Gas top-up prices in Singapore: R32 top-up typically runs $80 to $150 per unit. Leak tracing and repair is a separate charge depending on where the leak is. We quote both parts before we start.

3. Dirty evaporator or condenser coils

The problem. Behind the filter sits the evaporator coil (indoor) and outside sits the condenser coil (outdoor). Both are full of thin metal fins. When dust, dirt, mould or grease build up on these fins, the aircon cannot transfer heat properly. The gas and compressor may be fine, but the unit just cannot cool the room anymore.

In Singapore this happens faster than in colder countries because of our humidity, kitchen cooking, and the amount of fine dust in the air. If you live near a construction site, main road or MRT works, it is even worse.

Signs:

• Musty or sour smell when the aircon first switches on
• Unit runs fine but barely cools even with clean filters
• Black mould spots visible on the front panel or vents
• Outdoor unit fins look caked with dust or blocked by leaves

What to do. A chemical wash is the right answer if it has been more than 12 months since the last one, or if the unit smells. Price from $80 per unit.

If the coils are heavily soiled, or the unit has never been properly serviced, go for a chemical overhaul instead. The unit is fully dismantled, every part is cleaned separately, the fan motor is oiled, and everything is reassembled. Price from $180 per unit. It takes about 1.5 to 2 hours per unit but the cooling comes back like new.

4. Compressor problems

The problem. The compressor is the big box outside, on the ledge or roof. It pumps the refrigerant around the system. If the compressor is weak, failing or not starting at all, you get fan-only behaviour: air moves, but it is not cold.

Signs:

• Outdoor unit makes a loud humming, buzzing or clicking sound but the fan does not spin
• Breaker trips when the aircon starts
• Unit runs non-stop on coldest setting but the room never gets below 27 degrees
• Burnt smell from the outdoor unit

What to do. Do not open the outdoor unit yourself. Compressor work involves gas and mains electricity. Call a technician.

Often the compressor itself is fine but the capacitor that helps it start has failed. That is a small part inside the outdoor unit. A capacitor replacement in Singapore usually runs $80 to $180 depending on the brand and size. If the compressor itself is faulty, replacement cost varies by brand and model. For very old units (over 10 years), sometimes replacing the whole aircon is cheaper than a new compressor. We will tell you honestly which option makes sense.

5. Thermostat or control board issues

The problem. The remote, the sensor in the indoor unit, or the control PCB can all go wrong. The system thinks the room is already cold when it isn’t, so it stops cooling. Or the thermostat ignores the setpoint completely and just runs in fan mode.

Signs:

• The temperature number on the remote does not seem to match what the aircon actually does
• The aircon runs for 30 seconds then stops, over and over
• Blinking LED lights on the indoor unit (these are error codes)
• Outdoor fan never starts even though the indoor blower is on

What to do. First, try changing the remote’s batteries. Then unplug the aircon from the mains for 60 seconds and plug it back in to reset the board. If the problem continues, note down the blinking light pattern and send us a photo or short video on WhatsApp. Every brand (Daikin, Mitsubishi, Panasonic, LG, Samsung, Midea) has its own error code list, and the blinking pattern tells us exactly what is wrong before we even come.

6. Drainage, piping or installation issues

The problem. A lot of “aircon not cold” complaints in Singapore actually come from bad installation. Condensation does not drain properly, water backs up into the unit, the drain pipe is blocked, or the piping connecting indoor to outdoor units has a leak. Some older HDB installs also have insulation that has cracked with age, so the cold gets lost inside the trunking before reaching the room.

Signs:

• Water dripping from the front of the indoor unit
• Puddle under the outdoor unit
• Room closest to the compressor cools fine, farther rooms stay warm
• Gurgling sound from the indoor unit
• Copper pipes feel warm when they should feel cold

What to do. Drainage clearing is a common, simple job and is usually part of a general servicing. If the piping insulation is damaged or the installation itself was poor, it needs to be redone, and that is a bigger fix. Our technician will tell you what is actually going on after a 10-minute site check.

7. Wrong size unit for the room

The problem. An aircon that is too small will never cool the room on a hot Singapore afternoon, no matter what you do. An aircon that is too big will switch off quickly, leave the room humid and clammy, and keep cycling on and off.

Rough Singapore sizing guide for cooling only:

Signs:

• Aircon runs on max for hours but room stays at 28 degrees
• Room cools quickly but feels wet and sticky
• Unit turns on and off every few minutes

What to do. If the unit is the wrong size, no repair will fix it. You need to either upgrade the unit or add a second one. We do free sizing consultations if you are planning a new install or replacement.

8. Skipped servicing

The problem. The single most common reason we find for aircons not cooling properly in Singapore is simply that the unit has not been serviced in a year or more. All the other problems on this list (clogged filters, dirty coils, slow gas leaks, weak capacitor) creep in slowly when nobody is looking at the unit.

A Singapore aircon that runs 8 to 12 hours a day needs servicing more often than the same unit would in a colder, drier country. NEA guidance and every major brand (Daikin, Mitsubishi, Panasonic) recommend servicing every 3 months for heavy use, or at minimum every 6 months for light use.

What to do. Set up a quarterly or annual maintenance package. You get priority booking, a fixed price per visit, and a technician who already knows the condition of your units. Packages for 2, 3 and 4 unit HDB flats work out cheaper per unit than ad hoc servicing.

Quick price guide for Singapore fixes

Prices above are for standard residential units. For commercial, commercial aircon pricing is quoted per site.

When to stop troubleshooting and call us

Call 9654 0044 (or WhatsApp) straight away if:

• You can see ice on the indoor copper pipes
• The outdoor unit is humming loudly but not running
• The breaker trips every time the aircon starts
• There is a burnt smell from either unit
• Water is dripping onto the floor or ceiling
• The aircon has not been serviced in over a year

For these, DIY does not help. They need gas handling, electrical work or proper dismantling, and getting it wrong risks damaging the unit or yourself.

Why Singapore homeowners call VD Aircon for this

• BCA-registered, since 2016. Operated by Vedha Construction Pte Ltd (UEN 201624486M). Real office at 11 Mandai Estate, #02-04 ELDIX, Singapore 729908.
• 24/7 same-day response, islandwide. Tampines, Bedok, Jurong, Yishun, Sengkang, Hougang, Ang Mo Kio, Toa Payoh, Bukit Batok, Woodlands, Central, East Coast. We cover all of it.
• Every major brand. Daikin, Mitsubishi Electric, Mitsubishi Heavy Industries, Panasonic, LG, Samsung, Midea, Hitachi, Toshiba, Fujitsu, Sharp, Carrier.
• Honest diagnosis. If a chemical wash will do the job, we will not sell you an overhaul. If your 12-year-old unit is not worth saving, we will say so.
• Transparent pricing before we start. No surprise invoices after.

Book now: Call 9654 0044 or 9644 0652, WhatsApp the same number with a photo of the unit, or use the contact form. Most bookings within Singapore get a slot the same day.

Frequently asked questions

Why is my aircon blowing air but not cold in Singapore? The most common reasons in Singapore are dirty filters, low gas, dirty coils or a missed chemical wash. Nine times out of ten it is one of these four. A general servicing or chemical wash fixes most cases.

How do I know if my aircon needs a gas top-up? The clearest signs are cold air for the first few minutes then warm air, ice forming on the copper pipes, and a hissing sound near the pipes. Gas does not normally “run out”, so if it is low, there is a small leak somewhere that needs to be found and fixed before topping up.

How much does it cost to fix an aircon that is not cooling in Singapore? It depends on the cause. A chemical wash starts from $80 per unit. A gas top-up (R32) is $80 to $150 per unit. Capacitor replacement is $80 to $180. Chemical overhaul is from $180 per unit. We give a clear price before starting any work.

How often should I service my aircon in Singapore? Every 3 months if you run the aircon daily, every 6 months if you use it lightly. Singapore’s humidity and dust make servicing more important here than in cooler countries.

Can I do a chemical wash myself? No. A chemical wash uses specific chemicals that must be handled safely and flushed out completely. If done wrong, it can damage the coil and void your warranty. Normal filter washing at home is fine and encouraged.

Is it worth repairing an old aircon or should I replace it? As a rough rule, if your unit is over 10 years old and the repair cost is more than half the cost of a new unit, replacement usually makes sense. A new inverter unit also runs about 30 to 40 percent cheaper on electricity than an older non-inverter model. We will tell you honestly which makes sense for your case.

Do you handle condo and landed property aircons too, not just HDB? Yes. We service HDB flats, condominiums and landed homes across Singapore, including multi-system setups and VRV/VRF systems in landed homes.

Team Vedha

We specialize in Aircon installation, repair, and service. We have all type & model of recon compressor, full set & fancoil. Our technicians are highly proficient in their respective field and repairs and fixes aircon of various brands.