Most modern stoves come equipped with some form of secondary air control—which enables you to determine how much oxygen gets mixed with the fuel inside the firebox before it is burnt up! This helps your appliance run more efficiently and also reduces the amount of creosote that forms in your chimney (and on its lining) as well! Different types of fires require different levels of airflow, but for most pellets or softwoods, cutting off this supply altogether will help prevent smoke from coming out into your room while still allowing hot embers to burn away without causing damage anywhere else on the stove!