We always clean the filters, typically once or twice a year (vacuum and wash). And the outer casing which also gathers fluff/ dust. We found that more often (monthly) you may need to also keep the drains clear and clean them of mud hornets, ants nests, the odd dead insect and gecko eggs. All not that hard to do unless it’s the drain in the head.
We have never paid for a regular professional installer service (over 30 years). If a unit is loosing gas or otherwise faulty we assume it will soon be evident through a rapid loss of performance. That’s how car aircons which are really compact splits announce their failure. Some service orientated businesses may be leveraging our ignorance and insecurities?
We have however paid for another type of service for physical cleans of our large split systems which worked out at less than $200 per unit.
Experience suggests this will need to be done at around 5 years of summer use (on the hottest summer days and nights). It made sense to have a professional clean which includes a wash and disinfection. Some professional cleaning services we have used do this insitu and hence do not disturb the gas or electrics. We have used Sanitair previously. After nearly 15 years in regular summer use the units still performed as well as when new.
The installers who have the added cost of being licensed generally indicated they remove the whole unit - however for an older split type air con the added cost including a re-gas may make you think it will be cheeper to buy a new unit? Quotes in the past for cleaning by licensed installers have always been substantial. Interestingly some have referred us on to the insitu services, others have indicated they are the only people who can clean aircons. Perhaps if we lived next door to a quarry or cement plant with no enviro control we would need this level of service each year.
ps For the box type aircons we have always been able to clean these ourselves as access is that much simpler.
Perhaps Choice could test the relative performance of a couple of older aircons (average dirty to neglected) compared to after cleaning to give us all a feel for the relative savings in electricity and CO2. We don’t see there is any value in paying for an annual service/check or cleaning internally the hard to get to bits annually is probably unnecessary.