Air conditioners’ maintenance- what shall I do? (advices for filter cleaning, suitable temperature etc)

First of all the unit should be installed by an experienced and specialized technician. The filters and whole the indoor unit and the fins of the outdoor should be cleaned frequently. At least once a year a service should be done by a specialized technician and if a problem appears you should refer to the same technician. Every time a service is done, the outdoor unit should be cleaned properly, and the pressures should be checked the quantity of the refrigerant, optic, acoustical checks for the state of the unit and for unusual noises. The services should not be neglected, for if the unit does not operate properly (is dirty, operates at lower or higher pressures etc), the unit will be distressed without a reason, its life time will shorten and it will operate uneconomical.