The answer to 'when to service central air' is that you should have your central air conditioning system serviced at least once a year, typically in the spring before heavy use during the summer. This annual maintenance helps ensure your system is running efficiently and can identify any potential issues before they become major problems.
During a tune-up, an HVAC technician will inspect the system, clean the coils, check refrigerant levels, test electrical components, and make any necessary adjustments or minor repairs. They may also recommend replacing the air filter, which should be done every 1-3 months during peak usage.