Filters have a efficiency rating called MERV, ( Minimum Efficiency Reporting Value). The higher the MERV rating , the cleaner the air and the better the equipment protection. Control dust, dirt, and pollen with high quality filters and/or air cleaners.
A dirty indoor evaporator coil will hinder the unit's ability to cool the air moving through the unit. Have the coil cleaned regularly to maintain peak efficiency and control utility costs. If your filter has become blocked , it is likely that the coil is dirty also.