Start with the filter and the settings
The most common cause is also the easiest. A filter clogged with dust chokes the airflow so the room never cools even though the compressor is running.
Take the filter out, rinse it under a tap, dry it completely and refit it. While you are there, confirm the remote is on Cool rather than Fan, and that the set temperature is below the current room temperature.
Signs the refrigerant is low
If air comes out but never gets cold, and the copper pipe at the outdoor unit is icing up, the refrigerant charge is probably low. Refrigerant does not get used up — low means there is a small leak somewhere.
Topping up without finding the leak only buys a few months. A proper technician pressure-tests the system and traces the leak before recharging.
- Air blows but the temperature never drops
- Ice forming on the pipework or the coil
- The unit takes far longer than it used to
- A faint hissing near the indoor unit
Dirty coils and a blocked outdoor unit
An evaporator coil caked in greasy dust cannot transfer heat efficiently. It happens gradually, so most owners do not notice until performance has halved.
The outdoor unit needs breathing room too. Furniture, planters or a wall too close to it trap the heat it is trying to reject and force the compressor to work harder.
When to call a technician
If the filter is clean, the settings are right and the outdoor unit is clear but the room still will not cool, the fault is inside the system and needs pressure gauges.
We can assess the unit and quote before any work starts, so you are not paying for work that was never needed.