The indoor coil where refrigerant absorbs heat and moisture condenses out of your air. A dirty or frozen evaporator coil is behind many 'AC runs but doesn't cool' calls.
Around Baltimore, Annapolis, and the DC metro, cooling decisions revolve around humid Mid-Atlantic summers, correct sizing for row houses and older homes, SEER2 efficiency, and whether a repair or a planned replacement is the smarter long-term spend.