Why Is My AC Not Cooling? 7 Real Reasons & What To Do in Dhaka
You turned on your AC, the fan is blowing — but the room still feels like a furnace. This is one of the most common complaints we get at Rifat Refrigerator & Engineering from customers across Dhaka, especially as summer temperatures climb past 40°C. A running AC that is not actually cooling is frustrating, and if left unchecked, the underlying problem usually gets worse.
Before you call for service, it helps to understand what is actually going on. Some issues are straightforward DIY fixes. Others need a licensed technician with the right tools. This guide walks you through the seven most common reasons an AC stops cooling effectively — and what the right fix looks like for each.
The 7 Most Common Reasons Your AC Is Not Cooling
These are based on thousands of service calls across Dhaka City — from Uttara to Dhanmondi, Gulshan to Mirpur.
Dirty or Clogged Air Filter
Dhaka’s dust levels are among the highest in South Asia. A filter blocked with dust restricts airflow so severely that cold air cannot reach the room. This alone causes nearly 30% of “no cooling” complaints.
Low Refrigerant (Gas Leak)
Refrigerant does not “run out” on its own — if your AC is low on gas, there is a leak somewhere. Without enough refrigerant, the system physically cannot transfer heat. This always requires a technician.
Dirty Condenser Coils
The outdoor unit’s coils release heat outside. When they get caked with dust and grime — very common in Dhaka’s polluted air — the system cannot shed heat and cooling capacity drops sharply.
Faulty Compressor
The compressor is the heart of your AC. When it fails or weakens, cooling stops. You may hear a clicking sound or notice the outdoor unit running but producing no cold air from inside.
Thermostat or PCB Fault
The thermostat tells the AC when to cool. A malfunctioning thermostat or a damaged PCB board can cause the unit to run without engaging the cooling cycle at all, even on the lowest setting.
Wrong Capacity for Room Size
A 1-ton AC in a 250 sq ft room is fine. But in a 500 sq ft room with direct sunlight, it will run constantly and never reach the target temperature. Many Dhaka apartments have undersized ACs.
Refrigerant Overcharge
Too much gas is just as bad as too little. Overcharging — a mistake some untrained technicians make — reduces efficiency and can damage the compressor over time. Requires a proper pressure check.
1. Dirty or Clogged Air Filter — The #1 Culprit
Most homeowners in Dhaka have no idea how often their AC filter needs cleaning. The answer, during heavy use months, is roughly every three to four weeks. In dusty areas like Mirpur or near construction zones in Bashundhara, even more frequently.
When the filter is blocked, the evaporator coil inside the indoor unit gets too cold and can actually freeze over. Ice buildup on the coil blocks airflow further, turning your AC into a room heater in the worst cases.
Remove the filter panel (usually clips at the top of the indoor unit). Wash the filter gently under running water, let it dry fully, and reinstall. Do this every 3–4 weeks during summer. If you notice ice on the unit or water dripping, switch off the AC and call a technician.
2. Low Refrigerant / Gas Leak — Needs a Technician
Refrigerant circulates in a closed loop. If the level is dropping, the pipe has a crack, a valve is leaking, or a joint has loosened. Just topping up the gas without finding and fixing the leak is a waste of money — it will be low again within weeks.
Signs of a gas leak include: the AC runs constantly but never cools the room, ice forming on the copper pipe near the indoor unit, or a slight hissing sound near the outdoor unit. Our technicians use leak detection tools to find the exact point before adding any refrigerant.
Refrigerant handling requires certification and proper equipment. Incorrect gas charging (wrong refrigerant type or wrong pressure) will damage your compressor within months. Always use a licensed technician for gas work.
3. Dirty Condenser Coils on the Outdoor Unit
Dhaka’s outdoor air carries significant amounts of dust, vehicle exhaust particles, and industrial pollutants. Within one season, the condenser fins on your outdoor unit can become coated in a layer of dirt that acts as insulation — the exact opposite of what you need when trying to release heat.
The outdoor unit should be cleaned at least once a year using a low-pressure coil cleaner and a soft brush. High-pressure water jets should never be used directly on the fins as they bend the delicate aluminum easily.
4. Faulty Compressor
Compressor failure is the most expensive AC repair. It is also often preventable. The main causes of premature compressor failure in Dhaka are: voltage fluctuations without a voltage stabilizer, running the AC when refrigerant is critically low, and never cleaning the condenser coils — which forces the compressor to work at high pressure constantly.
| Symptom | Likely Cause | DIY or Technician? |
|---|---|---|
| Fan runs, no cold air | Low gas or compressor fault | Technician |
| AC trips the circuit breaker | Electrical fault or compressor shorting | Technician |
| Warm air blowing from indoor unit | Thermostat in “Fan Only” mode or gas issue | Check mode first; if not fixed, Technician |
| Ice on copper pipe near indoor unit | Low gas or blocked filter | Clean filter first; if persists, Technician |
| AC cools well, then stops after 10 min | Thermostat fault or overheating compressor | Technician |
| Water dripping from indoor unit | Blocked drain line or frozen coil | Clean drain line; if persists, Technician |
5. Thermostat or PCB Issue
Modern inverter ACs are controlled by sophisticated PCB (printed circuit board) modules. Power surges — which happen frequently during Dhaka’s load-shedding cycles — are a leading cause of PCB damage. When the board malfunctions, the compressor may not receive the signal to start the cooling cycle even though the fan is running perfectly.
Before assuming a PCB fault, always check: Is the thermostat set to “Cool” mode and not “Fan Only”? Is the set temperature lower than the room temperature? Sometimes the fix is as simple as switching the mode on the remote.
6. Wrong AC Capacity for Your Room
In Bangladesh, AC capacity is measured in tons or BTU. A 1-ton AC produces around 12,000 BTU per hour. For a standard room in Dhaka, these are rough guidelines:
| Room Size | Recommended Capacity | Notes |
|---|---|---|
| Up to 120 sq ft | 0.75 Ton | Small bedroom |
| 120–180 sq ft | 1 Ton | Standard bedroom |
| 180–250 sq ft | 1.5 Ton | Large bedroom / small living room |
| 250–400 sq ft | 2 Ton | Living room; add 0.5T if west-facing |
| 400–600 sq ft | 2.5–3 Ton | Open-plan or commercial space |
7. Refrigerant Overcharge
This is a less-discussed but real problem, particularly if your AC was recently serviced by an untrained technician who added gas without measuring pressure properly. Too much refrigerant raises the high-side pressure in the system, reduces efficiency, and creates excess load on the compressor. The symptoms can look identical to low gas — the AC runs but does not cool well. Proper diagnosis requires a manifold gauge set.
When To Call a Professional in Dhaka
You should call a technician immediately if:
- You smell something burning from the indoor or outdoor unit
- The AC trips your circuit breaker when turned on
- There is visible ice buildup on any part of the unit
- The outdoor unit makes a loud grinding or clicking noise
- Cleaning the filter did not fix the cooling issue after 24 hours
- The AC cools for a few minutes then stops cooling completely
AC Still Not Cooling After Reading This?
Our technicians are available every day 8AM to 12AM across all of Dhaka City. We find the problem first, quote the price, then fix it — no surprises.
Frequently Asked Questions
Why is my AC running but not cooling the room?
The most common reasons are a dirty air filter, low refrigerant gas, or dirty condenser coils on the outdoor unit. Start by cleaning the filter yourself. If the problem continues, the unit likely needs a gas check or coil cleaning by a technician.
How much does AC gas refill cost in Dhaka?
AC gas refill (refrigerant recharge) in Dhaka typically costs between BDT 2,000 and BDT 4,500 depending on the AC capacity and refrigerant type (R22, R32, or R410A). This should always include a leak check — a refill without fixing a leak is money wasted.
How often should I service my AC in Dhaka?
At minimum, once a year before summer. Given Dhaka’s dust levels, twice a year is ideal — once before the summer season (April) and once in October. Filter cleaning should be done every 3–4 weeks during heavy use months.
Can a dirty filter cause the AC to stop cooling completely?
Yes. A severely blocked filter causes the evaporator coil to freeze over. When the coil is iced up, no air can pass through at all and the indoor unit essentially stops cooling the room entirely. Cleaning or replacing the filter usually solves this within a few hours.
Is it safe to use the AC during Dhaka’s load-shedding cycles?
Not without a voltage stabilizer. Voltage fluctuations during load-shedding and reconnection spikes are a leading cause of PCB board damage and compressor failure in Dhaka. A good stabilizer is a worthwhile investment that can extend your AC’s life by years.