An exhaust system includes a hood structure having one or more of (i) an exhaust flow infeed surface extending downward from a lower end of the filter unit that helps to feed the thermal plume toward the filter unit, (ii) a bypass flow transition surface extending upward from the upper end of the filter unit and then forward to aid bypass flow in circulating back toward the filter aperture and (iii) a front wall structure that includes a downwardly extending wall portion with a chamfered and/or curved transition portion at its lower end and a rearwardly extending wall portion.