A system and method are disclosed for enhancing airflow through a vertically oriented spiral freezer or oven stack used for freezing or heating food product. At least one high-static fan assembly is mounted above a spiral stack assembly of the system to accelerate and direct air vertically through the spiral stack assembly. Air is directed through a heat exchanger via at least one circulation fan, cooling or heating the air via the heat exchanger. The cooled or heated air is vertically accelerated through the vertically oriented spiral stack assembly via at least one high-static fan assembly mounted above the spiral stack assembly. A method is also disclosed to retrofit a system having a vertically oriented spiral freezer or oven stack to enhance airflow through the stack.