A simple way to explain is that a central air conditioning system helps keep your home cool and reduces humidity levels. By transferring heat from air located inside your home to the outside, conditioned and cooled air is left to be re-circulated. Using electricity as its power source, the compressor inside an air conditioning unit pumps coolant, or refrigerant, back and forth to gather heat and moisture from indoors. Warm air from inside is blown over the cooling coil, which is connected to the compressor, and then pumped back into your home.