Our vertical wall-mount, front or bottom return air handler is a type of air handler unit that is designed to draw air in from the front or bottom of the unit, rather than from the sides or the back. This style of air handler is typically installed in a central location within a building, such as a mechanical room or utility closet. The air handler draws air in from the front grille or filter, passes it through the cooling or heating coil, and then pushes the conditioned air back into the ductwork for distribution.