Which component is responsible for exhausting products of combustion in a gas furnace?

The induced-draft fan is essential in a gas furnace for expelling products of combustion, such as carbon dioxide and water vapor, from the furnace to the outdoors. This fan operates by creating negative pressure, which helps to pull combustion gases through the heat exchanger and out of the venting system. It ensures that the combustion process operates efficiently and safely by preventing the backdraft of exhaust gases into the living space and maintaining proper airflow.

In contrast, the blower motor’s primary function is to circulate air throughout the home once it has been heated. The thermostat is responsible for regulating the temperature by signaling the furnace to operate or shut down based on the desired indoor temperature. The heat exchanger, while critical for transferring heat from the combustion gases to the air that circulates through the home, does not directly exhaust the combustion products. Therefore, the induced-draft fan is the correct answer as it is specifically designed for the task of venting these harmful gases.