The two main parts in a heating and cooling system are the evaporator unit and the condenser unit. The heating and cooling system works by moving air between the two systems. The air is heated or cooled through this process and recycled into the area being conditioned.
There are two types of HVAC systems: packaged systems and split systems. In a split system, the evaporator unit is indoors and the condenser is outside. In a packaged system, the condenser and evaporator are together in one unit and stored outdoors. If there is a furnace instead of a heat pump for generating heat, the furnace warms the air and moves it through the same duct work. If there is no furnace, the condenser and evaporator work together to move warm air into or out of a room being conditioned.