In Singapore, your aircon isn’t a luxury — it’s infrastructure. When it stops cooling properly, it’s not something you want to diagnose over a few days. Humidity kicks in fast, sleep suffers, and what starts as weak airflow can turn into a full breakdown if left alone.
The good news: most cases of an aircon not cooling have a specific, identifiable cause. This guide covers the 6 most common ones, what each means for your unit, and what needs to happen to fix it.
Why Is My Aircon Not Cooling?
1. Clogged Air Filters
This is the most common cause — and the easiest to fix. Your aircon’s filters trap dust, pet hair, and airborne particles over time. Once they’re clogged, airflow drops, your unit works harder, and cooling performance suffers noticeably.
In Singapore’s humidity, filters accumulate grime faster than in drier climates. If you’re running your aircon most of the day — which most households do — filters need attention every 3 to 6 months at minimum.
What to do: Schedule a professional servicing. A properly trained technician will clean the filters as part of a full unit service, not just a surface wipe.
2. Dirty Evaporator Coils
The evaporator coil is what actually absorbs heat from the air in your room. When it gets coated in dust and grime — particularly on the back of the coil where most cleaning methods don’t reach — it loses the ability to absorb heat effectively. The result: your aircon runs but the air coming out isn’t cold.
This is exactly why standard aircon servicing often falls short. Most providers clean only the front of the coil. Urban Company’s FoamJet servicing uses high-pressure foam to clean both the front and back of the evaporator coil, where the real buildup happens.
What to do: Book a FoamJet aircon service. From $23/unit, no contract required.
3. Low Refrigerant (Gas)
Refrigerant is the substance that makes cooling possible — it absorbs heat from indoor air and releases it outside. If your unit has a refrigerant leak, cooling capacity drops significantly. You might notice the air feels slightly cool but never reaches the temperature you’ve set.
Signs your refrigerant may be low:
- Air is less cold than it used to be, even on the lowest temperature setting
- Hissing or bubbling sounds from the unit
- Ice forming on the evaporator coil or copper pipes
What to do: This requires a professional. A technician will check for leaks, repair them, and top up the gas. Urban Company offers gas top-up from $49 for R22 refrigerant.
4. Blocked Condenser Unit
The condenser is the unit outside your home — on a ledge, in a yard, or in a dedicated aircon ledge in HDB and condo units. Its job is to release the heat that the indoor unit has absorbed. If it’s blocked by debris, dust buildup, or poor ventilation, it can’t do that job, and your whole system runs less efficiently.
In landed properties with outdoor condensers, leaves and plant matter are common culprits. In HDB and condo units, dust accumulation on the fins is more typical.
What to do: Keep the area around the condenser clear. Urban Company’s condenser cleaning service addresses this directly — from $49 for 1 unit.
5. Thermostat or Sensor Issues
Sometimes the problem isn’t the cooling system itself — it’s the thermostat misreading the room temperature and cutting the compressor too early. This can make it feel like the aircon isn’t cooling when it’s actually just stopping prematurely.
Check: is the aircon blowing cold air for a while and then switching to fan mode before the room feels cool? That pattern points to a thermostat or sensor issue rather than a coil or refrigerant problem.
What to do: Check your remote settings first — make sure you’re on Cool mode, not Fan mode, and that the set temperature isn’t too high. If settings are correct and the issue persists, a technician should inspect the sensor.
6. Compressor Failure
The compressor is the heart of the system. It circulates the refrigerant and drives the whole cooling cycle. A failing compressor usually means no cooling at all — the unit may run and blow air, but nothing gets cold.
Compressor issues are typically the most expensive repair. They’re also often the result of years of inadequate maintenance — dirty coils and low refrigerant both put extra strain on the compressor over time.
What to do: Call a technician for diagnosis. Urban Company charges a $60 diagnosis fee, which is waived if you proceed with the repair.
How Urban Company Fixes Aircon Not Cooling
Depending on what the technician finds, there are a few different service paths:
FoamJet Aircon Servicing
For units that aren’t cooling due to dirty coils or reduced airflow — which covers most cases — FoamJet servicing is the right starting point. High-pressure foam cleans both sides of the evaporator coil, restoring airflow and cooling efficiency. Every job includes before-and-after airflow measurements with an anemometer, captured in the app, so you can see the difference.
From $23/unit, or $20/unit on an annual contract.
Condenser Cleaning
For units where the outdoor condenser is contributing to the problem. From $49 for 1 unit.
Gas Top-Up
For units confirmed to have low refrigerant. From $49 for a half gas top-up of R22.
Aircon Repair
For diagnosed faults — water leakage, power issues, noises, or reduced cooling that servicing alone can’t fix. $60 diagnosis fee, waived if you proceed with the repair.
Why Regular Aircon Maintenance Prevents Most of These Problems
Most of the causes above — clogged filters, dirty coils, strain on the compressor — are preventable with consistent servicing. In Singapore’s climate, every 3 to 6 months is the right cadence for most households. If you’re running 3 or more units daily, lean towards every 3 months.
The cost of a missed service is almost always higher than the service itself. A $23 FoamJet service done regularly prevents the conditions that lead to a $160+ chemical overhaul or a compressor repair that runs into the hundreds.
FAQ
Why is my aircon running but not cooling the room?
The most common reasons are dirty evaporator coils, clogged air filters, or low refrigerant. All 3 reduce your unit’s ability to absorb and remove heat from the room. A professional service will identify which one applies to your unit.
How do I know if my aircon needs gas top-up?
Signs include air that feels slightly cool but never reaches the set temperature, hissing sounds from the unit, or ice forming on the coil or pipes. A technician can confirm with a pressure check.
How often should I service my aircon in Singapore?
Every 3 to 6 months, depending on usage. For households running aircon most of the day across multiple rooms, every 3 months is more appropriate. Annual contracts with Urban Company work out to $20/unit per service.
What is FoamJet aircon servicing?
FoamJet is Urban Company’s standard aircon service. It uses high-pressure foam to clean both the front and back of the evaporator coil — the back is where most dirt accumulates and where standard servicing doesn’t reach. Every job includes before-and-after airflow measurements captured in the app.
What’s the difference between aircon servicing and a chemical overhaul?
Servicing — done regularly — cleans the unit and maintains performance. A chemical overhaul is a more intensive process for units with heavy mould, rust, or blockage that regular servicing can’t clear. Regular FoamJet servicing is specifically designed to prevent the buildup that makes a chemical overhaul necessary.
How much does aircon repair cost in Singapore?
Urban Company charges a $60 diagnosis fee for repair jobs — covering water leakage, less cooling, power issues, and unusual noises. The fee is waived if you proceed with the repair. Full repair pricing is shown in the app before you commit.
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