Exhaust hood methods, devices, and systems are disclosed herein that improve the performance of short-circuit hoods. Such improvements can be provided relatively inexpensively by utilizing existing features of the structure of short-circuit hoods. The resulting enhancement in performance may exceed that of a regular exhaust hood while avoiding the pitfalls associated with make-up air injection into the exhaust hood recess. The components of the short-circuit system that inject make-up and/or conditioned air into the exhaust hood recess can be converted into a combination of horizontal and vertical jets at a lower edge of the exhaust hood. A retrofit jet generator can be installed into the short-circuit system outlets. A series of openings in the jet generator can generate the combination of horizontal and vertical jets at a lower edge of the exhaust hood when air from the make-up air or conditioned air source is supplied thereto.