What is the primary purpose of a furnace's venting system?

The primary purpose of a furnace's venting system is to expel combustion gases. When a furnace operates, it burns fuel to generate heat which subsequently creates combustion byproducts, including carbon monoxide, unburned fuel, and other gases. These combustion gases must be safely vented out of the home to prevent the build-up of toxic and hazardous substances within the living space.

Proper venting ensures that these gases are directed outside, mitigating risks associated with indoor air quality and potential health hazards. The design and installation of the venting system are critical for its effectiveness; it must allow for proper airflow and maintain necessary clearances, thereby ensuring safety.

While providing additional heat or helping to circulate air are important functions of a heating system in general, they are not the primary function of the venting system. The venting system’s design is specifically focused on the safe disposal of combustion gases, making it a crucial aspect of furnace operation and safety. Protecting the furnace from moisture, while potentially relevant, does not directly relate to the function of venting during the combustion process.