Why Is My AC Not Cooling? 7 Reasons & Expert Fixes
(Barasat, Kolkata)

Nothing is more frustrating than switching on your AC on a hot Kolkata summer day only to find the room stays warm. If your AC is running — the fan is blowing, the unit is on — but there's no cool air, one of these 7 issues is almost certainly the cause.

1. Low Refrigerant (Gas Leak)

Refrigerant (commonly called "AC gas") is the substance that actually cools the air. If your AC has a refrigerant leak, it physically cannot cool your room no matter how long it runs. This is the #1 cause of poor AC cooling in Barasat.

Signs of low refrigerant:

• AC blows air but it's warm or only slightly cool
• Ice or frost forming on the indoor unit
• Hissing or bubbling sound from the unit
• Higher electricity bills despite less cooling

Fix: A technician checks refrigerant pressure, identifies the leak, repairs it, and refills the gas. Do not simply "top up" gas without fixing the leak — it will leak again.

2. Dirty or Clogged Air Filter

The air filter traps dust and debris. When it gets clogged, airflow is severely restricted — the AC cannot move enough air over the evaporator coil to cool it properly. In dusty areas like Barasat, filters should be cleaned every 3–4 weeks during summer.

Fix: Slide out the filter (usually behind the front panel), rinse under water, let dry completely, and reinsert. If the filter is torn or damaged, replace it.

3. Dirty Condenser Coils (Outdoor Unit)

The outdoor unit releases heat from your home to the outside. If the condenser coils are covered in dust, leaves, or grime, heat cannot escape efficiently — so cooling performance drops sharply.

Signs: Outdoor unit feels extremely hot to touch; AC struggles to cool during peak afternoon heat.

Fix: Professional jet-wash cleaning of the outdoor unit. Never use a high-pressure jet directly on fins — they bend easily.

4. Faulty Compressor

The compressor is the heart of your AC. It compresses the refrigerant so the cooling cycle works. A failing compressor means the refrigerant never gets pressurised properly — resulting in zero or minimal cooling.

Signs: Loud clanking or grinding noise; AC trips the circuit breaker; outdoor unit starts but indoor unit stays warm.

Fix: Compressor repair or replacement. This is a major repair — get a proper diagnostic before replacing, as it's expensive.

5. Thermostat Set Incorrectly or Faulty

A simple but often overlooked cause. If the thermostat is set to "fan only" mode instead of "cool," or the temperature setting is higher than room temperature, the AC won't cool.

Check: Ensure the mode is set to "Cool" (❄️), temperature is set below current room temperature (24°C or lower), and the remote is working properly.

6. Frozen Evaporator Coil

If airflow is blocked (dirty filter, blocked vents) or refrigerant is low, the evaporator coil inside the indoor unit can freeze over. A frozen coil means zero cooling and possible water damage.

Signs: AC blows warm air; visible ice on the indoor unit; water dripping from the unit.

Fix: Switch off the AC and let it defrost for 1–2 hours, then fix the underlying cause (clean filter / fix refrigerant leak). Never run a frozen AC — it damages the compressor.

7. Blocked or Closed Vents & Leaking Ducts

If furniture is blocking supply vents, or if return air vents are closed, cooled air cannot circulate the room. In ducted systems, leaking ducts lose 20–30% of cooled air before it reaches you.

Fix: Ensure all vents are open and unobstructed. For duct leaks, call a technician for duct sealing.

AC Not Cooling: Repair Cost in Barasat (2026)

Issue	Approx. Repair Cost
Gas refill (R32/R410A)	₹1,500 – ₹3,000
Filter cleaning	₹299 – ₹499
Condenser coil jet wash	₹499 – ₹999
Compressor repair	₹3,000 – ₹8,000
PCB / thermostat replacement	₹1,200 – ₹4,000
Full AC service (comprehensive)	₹699 – ₹1,499

When to Call a Professional

If cleaning the filter doesn't solve the problem, always call a certified technician. Attempting to recharge refrigerant yourself is illegal (it requires certification) and dangerous. Mishandling the compressor can cause total AC failure.

Our technicians at AC Reparing, Barasat carry all tools and spare parts on the van, diagnose the exact problem before quoting, and fix it same day — with a 90-day warranty.