Layan villa AC losing its cooling between services — is the dust out here the reason?

That fade-after-service pattern in an open, dusty area like Layan is almost always interval, not a fault, the dust just loads the system far faster than in an established, greener community. The fine sand and construction dust out there clog the filters within weeks, then settle on the evaporator coil and act like a blanket, so the unit runs longer and colder-starved to hit the same temperature, which is exactly the cooling you feel dropping off. A healthy unit does this too if the maintenance interval is set for a normal area rather than a dusty one. So the fix isn't a repair, it's routine: check and rinse the filters roughly monthly through the summer instead of quarterly, and get the coils professionally cleaned more than the standard once a year. Booking AC coil and filter cleaning on a tighter schedule for a dusty-area villa holds the efficiency far better than waiting for it to fade and calling it a fault. A better-grade washable filter helps, but never denser than the unit is rated for, that chokes airflow a different way.