Nothing is more frustrating than an air conditioner that stops cooling properly in the middle of a Pakistani summer. With temperatures regularly exceeding 42°C in Islamabad, Rawalpindi, and Lahore during June and July, a malfunctioning AC is not just uncomfortable — it can be a health hazard.
At Aircon Services, our technicians respond to hundreds of “AC not cooling” calls every summer. Here are the seven most common causes we find — and what you should do about each.
1. Dirty or Blocked Air Filters
This is the single most common cause of reduced AC performance. When the indoor unit’s air filter becomes clogged with dust, airflow over the evaporator coil drops dramatically. The coil may freeze over, and cooling capacity can drop by 30–50%.
Fix: Clean your filters every 2–4 weeks during peak summer. Rinse under lukewarm water, allow to dry fully, and refit. This simple step alone restores most of the lost performance.
2. Low Refrigerant (Gas Leakage)
AC refrigerant does not get “used up” — if your system is low on gas, it means there is a leak somewhere in the refrigerant circuit. Low refrigerant reduces the system’s ability to absorb heat, resulting in warm air from the indoor unit, ice forming on the evaporator coil, and hissing sounds near the indoor unit.
Fix: Do not simply top up the gas without finding the leak. A qualified technician must identify and repair the leak before recharging to the correct pressure.
3. Dirty Condenser Coils (Outdoor Unit)
The outdoor unit’s condenser coil releases heat to the outside air. In Pakistan’s dusty environment, these coils quickly accumulate a layer of dust and debris that acts as insulation, preventing heat rejection and forcing the compressor to work much harder.
Fix: Have the outdoor coils professionally cleaned at the start of each cooling season and midway through summer for heavily-used systems.
4. Voltage Fluctuations Causing Compressor Issues
Pakistan’s power supply is notorious for voltage fluctuations. These directly damage AC compressors and PCB boards — particularly in non-inverter models. A compressor running on under-voltage draws more current than rated, generates excess heat, and degrades faster.
Fix: Install a stabiliser rated for your AC’s power consumption. Inverter ACs typically have wider voltage tolerance built in (170V–260V range), making them more resilient to load shedding and voltage variation.
5. Undersized AC Unit for the Space
An AC unit that is too small for the room or building it is serving will run continuously at full power and never reach the target temperature. This is common when ACs are installed without a proper load calculation, or when spaces are later extended or converted.
Fix: Have a qualified HVAC engineer calculate the actual cooling load. For offices, this includes heat from people, computers, lighting, and sun exposure — not just floor area.
6. Clogged Condensate Drain
When the condensate drain becomes blocked, water backs up into the indoor unit. Many units have a safety float switch that shuts down the system when this happens. You may notice water dripping from the indoor unit before shutdown.
Fix: Clear the drain line. A technician can flush the line with compressed air or water. Regular AMC servicing prevents this recurring.
7. Faulty or Ageing Compressor
The compressor is the heart of any AC system. If the compressor is worn, has developed a fault, or its capacitor has failed, the system will blow air but with little or no cooling effect.
Fix: Compressor replacement is a major repair. For older systems, it is often more cost-effective to replace the entire unit.
When to Call a Professional
If cleaning filters does not resolve the issue, always call a qualified HVAC technician. Attempting to recharge refrigerant, open the refrigerant circuit, or repair electrical components yourself is dangerous and may void your warranty.
Aircon Services provides same-day and next-day repair service across Islamabad and Rawalpindi. Our certified technicians carry diagnostic equipment and common spare parts to resolve most faults in a single visit.
📞 0311-5237771 / 0334-8507771 | 📧 aircon_services@hotmail.com
