The draft inducer blowers purpose is to move air and gases out of the furnace
The draft inducer blower is also responsible for the quantity of air actually moving through the heat exchanger
This helps to move air efficiently and provides a more controlled method for air movement through the blower housing
As such it helps determine the efficiency of the system more precisely in addition to help run your heating system safely
In terms of drafting a draft inducer blower provides sufficient draft (just like the chimney in your fireplace that provides a draft) for clean and safe combustion
This clean combustion prevents burners from getting clogged with soot over time and creates a more balanced pressure in the combustion chamber