Why is my air conditioner not cooling?
An air conditioner that runs but doesn't cool usually comes down to one of two things: low refrigerant caused by a leak, or a failed start capacitor stopping the compressor from turning over. Both need a technician — but before booking, check the filters, because a dust-clogged filter drastically cuts cooling power.
How to recognise it
- The fan runs but the air comes out at room temperature
- Cooling is far weaker than it used to be
- The outdoor unit won't start, or starts and cuts out
- Ice forming on the gas pipework outside
Common causes
Low refrigerant from a leak
Refrigerant isn't consumed in normal use. If it's low, there is a leak. Simply topping it up buys a few months before the same fault returns, so the leak has to be found and repaired rather than just refilled.
Failed start capacitor
The capacitor gives the compressor its starting push. When it fails, the fan keeps running but the compressor never engages — so the unit blows air without cooling it.
Blocked filters or evaporator
A layer of dust restricts airflow and cuts cooling. This is the most common cause of all, and usually calls for a deep clean rather than a repair.
How we handle it
- 1Pressure-testing the system to establish whether refrigerant is low
- 2Metering the capacitor and compressor
- 3Leak detection where refrigerant is found to be low
- 4An itemised quote before any work begins
Want us to take a look?
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