As with your car its important to get your HVAC system serviced regularly. In central Texas where most systems perform both heating and cooling functions this should be twice a year in the Fall and Spring.
HVAC Filter Replacement
Its important to use the proper size and type of air filter with your HVAC system. Also, timely and regular replacement of the filter is important. Find out from your HVAC professional which type of filter your system should use and how often it should be replaced.
Regular HVAC Maintenance