What is the main function of a damper in a chimney?

The primary function of a damper in a chimney is to control airflow and the exit of smoke. When a damper is opened, it allows smoke and combustion gases to exit the fireplace or stove and disperse through the chimney, effectively facilitating proper ventilation. Conversely, when the damper is closed, it helps to prevent heat from escaping, which can be particularly beneficial when the fireplace is not in use. This control over airflow is crucial for efficient combustion, ensuring that fires burn effectively and safely, while also minimizing the risk of smoke buildup in the home.

The other choices, while they touch on important chimney functions, do not accurately describe the primary role of a damper. Odor prevention and structural support are managed through other components of the chimney system, while flue liners serve a different purpose related to safety and combustion efficiency.