How often should you service air conditioning?

A split air conditioning system that is never serviced will usually keep running, just less well: weaker cooling, higher running costs, and a slow build-up of problems that eventually show up as a breakdown at the worst possible time, typically the first hot week of the year.

Once a year is the standard, for a specific reason

An annual air conditioning service checks the filters, the condensate drain, the refrigerant charge and the outdoor condenser unit, which is usually the part people never look at because it is outside and out of sight. A blocked filter alone can cut cooling performance noticeably and make the unit work harder to do the same job, which shows up on the electricity bill before it shows up as a fault.

What actually goes wrong without one

• Filters clog with dust, reducing airflow and cooling capacity.
• The condensate drain blocks, and the unit starts dripping or leaking indoors.
• A slow refrigerant leak goes unnoticed until the system stops cooling properly.
• The outdoor condenser gets covered in debris and loses efficiency.

Any of these can eventually mean an air conditioning repair callout for something a routine service would have caught early and cheaply.

If the unit is older or was never serviced

A system that has gone several years without a service is worth having checked properly rather than just switched on for the first warm week, particularly if it uses an older refrigerant. F-Gas regulations mean only a registered engineer can legally handle the refrigerant side of it, so this is not really a DIY job beyond changing an accessible filter yourself.