Where is the return air on upflow furnace?

In an upflow furnace, the return air typically enters through the bottom or sides of the unit. It is drawn in from the living space through return air ducts, which then channel the air back into the furnace for heating. The heated air is then expelled from the top of the furnace into the ductwork, distributing warm air throughout the home. Proper placement of return air vents is essential for efficient airflow and heating comfort.