One way to heat your home with oil is to use a hot water system in which hot water circulates throughout baseboards or radiators in response to the temperature falling below what the thermostat is set on. When this happens, the thermostat signals the heating process to begin.
Another way to heat your home with oil is to use a steam system. This system turns water into steam, which then rises up through your radiators and pipes.
A third way to heat your home with oil is to use a warm air system. In this system, a furnace heats the air. Afterwards, a blower distributes heated air throughout ducts and out of vents in the walls and floors. A return duct brings the air back into the furnace so that the cycle repeats as needed.
For hot water, steam and warm air systems, an oil tank provides the fuel. The oil burner engages, and the heating oil travels from the tank to the burner through a pump, becoming a mixture of mist and air injected into a burner where it ignites within a combustion chamber.
Regardless of which method you use, the emissions created by the air and fuel combustion exit your system through a pipe that runs out of your home and through the chimney.