Short answer
For a typical Brisbane home, once a year before summer works well. Systems that run hard year-round, units in dusty environments, and anything near the bay benefit from being looked at more often. The most useful timing is late winter or early spring: a system that is going to struggle in January is far easier to deal with in September than during the first heatwave.
What a service actually covers
A genuine service is mostly cleaning, plus checks:
- Filters cleaned or replaced to restore airflow
- Indoor coil cleaned, which is where lost cooling capacity usually hides
- Blower barrel cleaned, the usual source of musty smells
- Condensate drain and tray cleared so water leaves the unit
- Outdoor coil and surrounds cleared so the unit can reject heat
- System run up and checked to confirm it is performing as it should
Why Brisbane is harder on systems
Humidity is the main factor. Dust settles on the indoor coil and then stays damp, which is what produces the musty smell on start-up and what gradually restricts airflow.
Near the bay, salt adds corrosion to the outdoor unit on top of that. Coastal systems generally warrant more frequent attention than inland ones.
Signs you are overdue
Any of these suggests a service sooner rather than later:
- A musty smell in the first minutes of operation
- Noticeably reduced airflow from the indoor unit
- The system running longer to reach the same temperature
- Water dripping or spitting from the indoor head
- Visible dust or dark spotting on the vanes
- Running costs climbing without a change in use
Will servicing lower my power bill?
A choked filter and dirty coil make a system work harder for less cooling, so restoring airflow usually helps.
Nobody can honestly promise you a specific saving, because it depends on how restricted the system had become and how you use it. Be cautious of anyone who quotes you a percentage.
What you can do between services
Washing the accessible filters every few months is genuinely worthwhile and takes minutes. Check the manual for how they come out.
Keeping the outdoor unit clear of leaves, cuttings and stored items also helps, since it needs unrestricted airflow to reject heat.
What you cannot reach is the indoor coil and blower barrel, which is where most of the performance loss and smell actually originates.
General guidance. Work involving the refrigerant circuit must be carried out by an ARCtick authorised technician.