What effect does a tall chimney have on draft?

A tall chimney improves draft due to the principles of thermodynamics and fluid dynamics. The height of the chimney creates a stronger upward pull on the combustion gases as they rise. This is known as the stack effect, where the temperature of the gases inside the chimney is typically higher than the outside air temperature. This difference in temperature creates a difference in pressure, leading to increased airflow through the chimney.

The taller the chimney, the more potential energy the rising gases have, which enhances the draft. This improved draft helps to ensure that combustion appliances receive enough air for optimal burning and effectively expels combustion gases, reducing the risk of backdrafts and enhancing the overall efficiency of the system.

Understanding this relationship between chimney height and draft is crucial for maintaining efficient and safe fireplace and heating stove operations.