AC not cooling? Common causes and what to do

When an AC runs but blows warm or barely cool air, the cause is often a wrong setting, dirty filters or a blocked outdoor unit, and all three can be checked in about 15 minutes. If the air is still warm after that, the likely cause is low refrigerant gas from a leak, a dirty coil, a failed capacitor or compressor, a unit too small for the room, or, in buildings with a central chilled-water system, a problem with the building supply. Those need a technician or the building management.

Check these first

These checks are safe and need no tools.

1. Mode and temperature. The remote or thermostat should show Cool, not Fan, Dry or Auto, with a set temperature clearly below room temperature, for example 23–24°C. Faint displays need new batteries, and sleep or eco modes are best switched off for the test.
2. Filters. Washing dusty filters and waiting 15 minutes often restores airflow. After a sandstorm, filters can clog within days.
3. Outdoor unit. On a split system, the outdoor unit needs free space around it: no boxes, covers, plants or sand drifts. Its fan should spin and blow warm air out. On a window unit, the outer side should not be blocked.
4. Doors, windows and sun. Closed doors and windows and drawn curtains against the afternoon sun make a big difference in summer.
5. After a power cut. Many units wait a few minutes before the compressor restarts. A wait of 5–10 minutes comes before any conclusion.

The unit should not be opened, and the wiring and refrigerant are not for home repairs. The outdoor unit holds electrical parts that stay charged, and handling refrigerant needs proper tools and training.

Read the symptoms

What happens	Likely cause	Who fixes it
Weak airflow from the indoor unit	Dirty filters or dirty indoor coil	Filters at home; coil by a technician
Strong airflow, but the air is only cool, not cold	Low gas, dirty coils or an undersized unit	Technician
Ice on the indoor coil or the copper pipes	Very low airflow or low gas	Technician (unit off until the ice melts)
Outdoor fan not spinning, humming or clicking	Capacitor, contactor or compressor	Technician
Error code or blinking lights	The unit has detected a fault	Technician (a photo of the code helps)
Cold in the morning, warm every afternoon	Undersized unit, strong sun or dirty outdoor coil	Technician or a larger unit
Fan coil runs but the air is not cold, in a building with central chilled water	Chilled water supply, valve or thermostat	Building management first

Causes that need a technician

Low refrigerant gas

An AC is a sealed system and its gas does not get used up. Low gas means a leak. A good technician finds and fixes the leak first, then evacuates the circuit and recharges by weight. A top-up without a leak check often means the room is warm again within weeks, and the bill is paid twice.

Dirty coils

Dust and humidity coat the coils, so heat cannot leave the room. If the last service was more than 6 months ago, AC cleaning comes before any repair. Units that smell musty or have gone a year without service may need a deep clean.

Capacitor, contactor or compressor

The capacitor helps the compressor and the outdoor fan start, and it often fails in summer heat. A capacitor or contactor is a fairly small repair. A failed compressor is the most expensive one, and on an older unit a technician may suggest comparing the repair price with a new unit.

Unit too small for the room

A 1 ton (12,000 BTU) unit in a large, west-facing room or a top-floor room under a hot roof will run all afternoon and never feel cold when it is 45°C outside. Nothing is broken; the unit is undersized. The guide on what size AC is needed shows the right capacity before money goes into repairs.

Buildings with central chilled water

In some towers and compounds, each apartment has fan coil units that only blow air over pipes with chilled water from the building plant. If the fan runs but the air is warm, the cause can be a closed valve, a faulty thermostat or the supply itself. The building management or facility team should be the first call; a private technician cannot add gas to this type of system.

What it costs

Service	Typical price in Saudi Arabia
Repair visit, split or window unit	from SAR 89, quote after inspection
Standard AC cleaning, split unit	SAR 80–150 per unit
Gas refill (R410a) with leak test	SAR 180–350
Capacitor replacement, parts and labour	SAR 120–250
Compressor replacement, parts and labour	SAR 900–2,200
Fan motor or control board (PCB)	quoted after inspection

Central, cassette and rooftop systems usually cost more than these residential split prices. A unit that cools poorly also runs longer: at 18 halalas per kWh up to 6,000 kWh a month and 30 halalas above, plus 15% VAT, the AC electricity cost calculator shows what that adds to the bill.

What to tell the technician

1. Brand, type (split, central or concealed, window), inverter or not, and the size in tons or BTU from the label.
2. Age of the unit and the date of the last service.
3. What happens: warm air, weak air, ice on the pipes, noises, a tripping breaker.
4. Any error code, with a photo.
5. Where the outdoor unit is (balcony, roof, ground) and whether the compound or building registers workers at the gate.

It is worth asking what the visit fee is, whether it is deducted from the repair, and whether a leak check comes before any gas is added.

If the quick checks did not help, the symptoms can be described once on khalasna to compare quotes from up to 5 AC repair companies, for example in Jeddah, with the visit fee and warranty clear before anyone arrives.

Frequently asked questions