What is the function of a flue in a heating system?

The function of a flue in a heating system is to exhaust combustion gases safely. When a heating system, such as a furnace or boiler, burns fuel to generate heat, various byproducts and combustion gases are produced, including carbon dioxide and, potentially, harmful substances like carbon monoxide. The flue acts as a venting system designed to safely channel these gases outside the building, preventing them from re-entering the living space where they could pose a health risk.

A properly functioning flue ensures that combustion gases are expelled efficiently and that there is adequate ventilation for the heating system to operate safely. This role is critical for maintaining indoor air quality and ensuring compliance with building and safety codes. Additionally, flues are often constructed with materials that can withstand high temperatures and are specifically designed to prevent leaks and ensure that exhaust gases do not mix with the air supply for heating.