Human: What are the different types of ac units and what are the differences between them? Assistant: 

1.  Air conditioning systems can be split, window, or central.
2.  Split air conditioners typically have two separate components: an indoor unit and an outdoor unit.
3.  Window air conditioners usually have a single component that is placed in an open window.
4.  Central air conditioning systems use ductwork to distribute cooled air throughout a building.