What is the purpose of a chimney?

The purpose of a chimney is primarily to convey flue gases to the outside atmosphere. This function is critical for ensuring that harmful combustion byproducts, such as carbon monoxide, smoke, and other gases produced during the burning of fuels, are safely expelled from a structure. By directing these gases outside, chimneys help maintain indoor air quality and prevent the accumulation of toxic substances within living spaces.

Chimneys also play a role in promoting proper airflow and fuel efficiency for heating appliances, ensuring they operate safely and effectively. While some of the other options may relate to the overall functionality of heating systems, they do not capture the core raison d'être of a chimney, which is the safe removal of flue gases.