What is the primary purpose of a flue or chimney in gas appliances?

The primary purpose of a flue or chimney in gas appliances is to vent exhaust gases safely outside. When gas is burned, it produces combustion gases, including carbon monoxide, which are harmful if allowed to accumulate indoors. The flue or chimney provides a crucial pathway for these gases to exit the building, ensuring that the indoor environment remains safe and breathable. By directing exhaust away from living spaces, the flue system helps to prevent the risk of carbon monoxide poisoning and allows for the safe operation of gas-burning appliances.

Enhancing energy efficiency, providing a pathway for fresh air, and reducing noise from the appliance are important considerations for appliance design but are secondary to the essential function of safely venting harmful gases. Thus, the primary and most critical role of a flue or chimney is ensuring that exhaust gases are directed outside effectively.