A central air conditioner is like a giant refrigerator of your home. In fact, it is built the same types of components, materials, and systems as a refrigerator, including a refrigerant that changes from liquid to gas and back to a liquid as it travels through a system of tubes and coils or fins that collect and kill off heat. As it goes through this cycle, it gathers heat from one place and transfers it to another. At the same time, it creates cold (the absence of heat) in one place and delivers that chill to another. In the case of an air conditioner that place receiving the cold is an air handler or furnace cabinet that is equipped with a blower that pushes the chilled air throughout your hall.