Five checks to do before you call anyone
- Thermostat and mode. Make sure it is set to Cool, not Fan or Dry, and that the set temperature is below the room temperature. Replace the batteries in a wireless thermostat or remote if the display is faint.
- Fan speed and airflow. Put the fan on medium or high and hold your hand to the grille. Weak airflow points to a blocked filter, a dirty coil or, in ducted systems, a closed damper or crushed duct.
- The filter. Open the indoor unit or return-air grille and look at the filter. If it is grey or matted with dust, wash or replace it, let it dry and refit it.
- The outdoor unit. Check that its fan is spinning and that nothing is stacked against it. Leaves, plastic sheeting, stored furniture or a fresh layer of sand all stop it releasing heat.
- The breaker. If the indoor unit runs but the outdoor unit is silent, check whether its breaker has tripped. Reset it once; if it trips again, leave it off and call a technician.
If the room starts cooling within 30 minutes of a filter clean or clearing the outdoor unit, you have found the cause. If not, one of the faults below is likely.
The common causes, and what each one looks like
| Clogged air filter | Weak airflow from the grilles, the room cools slowly, dust around the vents. The most common cause in Dubai homes. | Owner: clean or replace the filter. |
| Dirty indoor coil | Airflow is weak even with a clean filter, and the unit may smell musty. Dust that got past the filter coats the coil and stops it absorbing heat. | Technician: chemical coil wash. |
| Dirty or blocked outdoor unit | Cools at night but struggles in the afternoon heat. The outdoor coil is caked in dust or the unit has no room to breathe. | Technician: wash the condenser coil and check the fan. |
| Low refrigerant (gas leak) | Runs constantly without cooling, ice on the copper pipes or coil, sometimes a hissing sound. | Technician: find and repair the leak, then recharge. |
| Failed capacitor or fan motor | The outdoor unit hums but its fan does not spin, or it starts and stops. Common after the hottest months. | Technician: replace the part. |
| Compressor fault | The indoor fan runs but the air is never cold and the outdoor unit clicks or stays silent. | Technician: diagnose; repair or replace. |
| Thermostat or sensor fault | The unit switches off too early, ignores the set temperature or shows error codes. | Technician: test and replace the sensor or control. |
| Duct leaks or closed dampers | In ducted villas, some rooms are cold and others warm, or the ceiling space feels cold. | Technician: inspect and seal ducts, balance dampers. |
| Chilled-water supply issue | In apartments on district cooling, every fan coil in the building is weak at once. | Building management or the cooling provider. |
Why Dubai is so hard on air conditioners
Air conditioners here run for most of the year and almost continuously from June to September. Afternoon heat makes the outdoor unit work hardest exactly when the house needs the most cooling, and fine dust settles on filters and on both coils far faster than in a temperate climate. A unit that cooled well in April can lose much of its capacity by August if nobody has cleaned it, which is why most AC breakdowns are booked in the hottest weeks.
Apartments connected to district cooling use chilled-water fan coil units instead of a refrigerant system. They have no compressor in the apartment, but the filter, coil, fan and thermostat can still fail in the same way. If one room is warm, the fault is usually in that fan coil; if the whole building is warm, contact building management.
What you can safely do yourself
- Clean or replace filters monthly in summer and after dust storms.
- Keep the outdoor unit clear on all sides and gently rinse loose dust from its fins with low-pressure water, with the power off at the breaker.
- Close curtains and blinds on sun-facing windows in the afternoon to cut the heat load.
- Avoid setting the thermostat very low to cool a room faster; it does not cool faster and can make the coil ice over.
Leave refrigerant, electrical parts, capacitors and the inside of either unit to a qualified technician. Adding gas without finding the leak, or opening a unit while it is powered, is unsafe and usually makes the repair more expensive.
When to switch off and call a technician
- The unit blows warm air after the filter and outdoor unit have been checked
- Ice or frost on the coil or copper pipes
- A burning smell, buzzing, or the breaker trips more than once
- Water dripping indoors as well as poor cooling. See why an AC leaks water.
- Error codes on the indoor unit or thermostat
How a technician finds the fault
A proper diagnosis measures rather than guesses. The technician checks the filter and airflow, measures the temperature of the air going in and coming out, inspects and cleans the coils, tests the capacitor, fan motor and compressor, and connects gauges to check refrigerant pressure if a leak is suspected. In ducted systems the ducts and dampers are checked too. JServices technicians explain the fault and the fix before starting, and you receive a fixed price before any work begins.
How to keep it cooling all summer
- Before summer: book a full service for every unit, with both coils washed and refrigerant checked. See when to service your AC in Dubai.
- Monthly in summer: check filters and listen for changes in how the outdoor unit sounds.
- After a dust storm: recheck filters and rinse the outdoor unit.
- All year: follow the villa maintenance checklist for Dubai, or let a JServices annual care plan schedule the visits for you.
Related services
Questions
Why is my AC running but not cooling?
The most common reasons are a clogged air filter, a dirty indoor coil, an outdoor unit that cannot release heat because it is dusty or blocked, a thermostat set to the wrong mode, low refrigerant from a leak, or a failed capacitor or fan motor. Filter and thermostat problems you can check yourself; the others need a technician.
Should I turn off an AC that is not cooling?
Yes, if it is blowing warm air, has ice on the coil or copper pipes, smells of burning or keeps tripping the breaker. Running it in that state wastes power and can damage the compressor, which is the most expensive part to replace.
Can low gas stop an AC from cooling?
Yes. An AC does not use up refrigerant, so low refrigerant means there is a leak. Signs are ice on the pipes, a hissing sound and a unit that runs constantly without cooling. A technician should find and repair the leak before recharging, otherwise the problem returns.
Why does my AC cool at night but not in the afternoon?
On the hottest afternoons the outdoor unit has to reject heat into very hot air. If its coil is dusty, its fan is weak or it sits in direct sun with poor ventilation, it can no longer keep up, so the room warms during the day and recovers at night. Cleaning the outdoor coil and checking the fan usually helps.
How often should AC filters be cleaned in Dubai?
Check filters every month in summer and after dust storms, and clean or replace them whenever they look grey. Most Dubai homes need a full service with coil cleaning at least twice a year.
Does JServices fix ACs that are not cooling?
Yes. JServices repairs split, ducted, VRF and chilled-water fan coil units in villas and apartments across Dubai, responds 24/7 and aims for same-day visits. Send a photo on WhatsApp to +971 56 198 7703 and you receive a fixed price before any work begins.
Need help?
Send a photo or a note on WhatsApp and receive a fixed price and a time slot, often the same day. Serving Emirates Hills, Palm Jumeirah, Jumeirah Golf Estates, Dubai Hills Estate and most of Dubai.
WhatsApp +971 56 198 7703info@jservices.llcUpdated 2026-10-07. Written by the JServices team. General guidance only; electrical, gas and refrigerant work should be carried out by qualified technicians.