What is a Chimney and what does it do?
A chimney, simply put, is a vertical tube designed to take the combustion products (smoke and gasses) from the appliance (like a wood stove, fireplace, heater) to the atmosphere outside your home, and at the same time, to draw air for combustion into the appliance. This movement of combustion air and exhaust is called draft. In essence, it is the difference in pressure between the air/gasses inside the chimney flue and the outside air that creates this movement. Warmer, lighter gasses in the flue tend to move upward. To keep the pressure conditions favorable, we need a tall column of warm air inside the chimney, and cooler air outside. The warm air will tend to rise, drawing the exhaust from the appliance out. As air exits the chimney, fresh air for combustion is drawn into the appliance.
