If your air conditioner is running but not cooling, the cause is often something you can check yourself. Before calling a technician, work through these four common issues and save yourself time and money.
Discovering the unit isn't working properly during a heatwave is frustrating. Emergency call-outs are expensive, and availability is often limited in peak summer. Regular maintenance, as we cover in our article on cleaning your air conditioner, can prevent most of these problems before they happen.
1. Dirty air filter
A clogged filter is the single most common reason an air conditioner stops cooling effectively. When airflow through the ducts is restricted, the thermostat can't read temperatures accurately and the system struggles to keep up.
A severely blocked filter can also cause the evaporator coil to freeze over, which completely stops cold air from circulating. Always start here: check the filter and clean it. It takes a few minutes and solves the problem surprisingly often.
2. Dirty or damaged outdoor unit
The outdoor unit can also be the culprit. Dirt, leaves, and debris build up around the condenser and restrict airflow, reducing the unit's ability to expel heat.
Check that the outdoor unit is clear and unobstructed. A simple clean is usually enough. If performance doesn't improve, there may be a fault with the fan or motor, and a qualified technician will need to take a look.
This doesn't apply to split-free or portable units without an outdoor component.
3. Thermostat or remote control settings
It sounds obvious, but wrong settings are a surprisingly common cause. If you use the unit for heating in winter, it may still be set to heat mode when summer arrives.
Check the selected mode: the sun symbol means heating, the snowflake means cooling. Switching modes takes seconds and can fix the issue immediately.
4. Refrigerant
A common misconception is that refrigerant gets used up over time. It doesn't. The refrigerant circuit is sealed, so the fluid doesn't deplete through normal use. If levels are low, it means there's a leak, typically from a damaged pipe or a poor installation.
The correct fix is to find and repair the leak first, then recharge the refrigerant. Topping it up without fixing the leak is pointless. If a technician suggests a recharge without any mention of a leak check, get a second opinion.
Buy a new air conditioner
If you've worked through all of the above and the unit still isn't cooling properly, it may be time to replace it. Read our guide “Which air conditioner to choose: a quick guide” for an overview of what's available on the market today.
Browse our full air conditioning range in our online shop.