A vertical evaporator coil is used for furnaces in the vertical position (upflow or downflow). The physical dimensions of the vertical cased coils here correspond to the various widths of Goodman furnaces available on our website, and are designed to fit correctly with the furnace. Typically a cased coil (whether vertical or horizontal) would be selected when installing a new furnace at the same time. If you are adding air conditioning or a heat pump system to an existing furnace, then an uncased coil is best.