An evaporator for disposition along an air flow for cooling the air. The evaporator comprises a continuous serpentine tube having an inlet and an outlet and a plurality of inner fins attached to the serpentine tube. The serpentine tube including at least one column of tube runs. The tube runs are grouped into tube run sets. Each tube run set is defined by at least one reverse bend and the tube runs extending from the ends of the at least one reverse bend. The centerline of each tube run set is not parallel to the centerline of an adjacent tube run set. Each inner fin extends between at least two tube runs of a tube run set.