Checks you can do yourself
- Mode and temperature: make sure the remote is on Cool, not Fan or Dry, and set below the room temperature.
- Dirty filters: open the front panel and look. Clogged filters are the most common cause of weak cooling. Wash them in water and dry them in the shade.
- Outdoor unit: it must be able to release heat. Clear rubbish, plants and covers, and make sure it is not boxed in or facing a wall.
- Doors, windows and sun: an open door or a sun-baked west window can beat even a correctly sized AC.
- Remote batteries and timers: weak batteries or a sleep or timer setting can change what the AC is doing.
Problems that need a technician
- Low gas: a leak somewhere in the circuit. Signs are ice on the pipes or long running with only mildly cool air.
- Dirty coils: dust on the indoor or outdoor coil blocks heat transfer, even with clean filters.
- Low voltage: the compressor struggles or trips. A voltage reading during the problem tells you if supply is the cause.
- Electrical faults: for example a failed capacitor on a non-inverter, which stops the compressor or fan from starting.
If the indoor unit shows an error
Many inverter ACs show a code or flash a light when they detect a fault. Note the code or the pattern of flashes and share it with your technician. It points them to the cause much faster.
When the AC is simply too small
If the AC has always struggled in that room, it may be undersized. Top floor rooms, west-facing walls and busy rooms need more cooling than the floor area suggests.
Frequently asked questions
Why is my AC running but not cooling?
Most often a clogged filter, the wrong mode, or an outdoor unit that cannot release heat. If those are fine, it may be low on gas, have dirty coils or be getting low voltage, which need a technician.
Why is ice forming on my AC pipes?
Usually restricted airflow from a dirty filter, or low gas from a leak. Switch the AC off, clean the filter and let the ice melt. If it comes back, call a technician.
Can low voltage stop an AC from cooling?
Yes. A compressor that does not get enough voltage may struggle or trip. Inverter ACs usually cope better, but very low voltage affects any AC.
