This paper presents a detailed review of the research carried out for the design of flat fin heat exchangers is using theoretical, experimental, and computational fluid dynamics (CFD) methods. The scope and limitations of several studies are presented, as well as the critical point of view of the authors in the selection of optimal methods in the thermo-hydraulic design of each equipment. Fin heat exchangers optimization is done using different approaches. The theoretical model assumes considerations that do not fully replicate the phenomenon, the experimental method provides real parameters for the design and implies high costs, and finally, computational fluid dynamics predicts the behaviors of thermal and hydraulic machine flows, in addition to recreating the phenomena almost exactly and complement the theoretical and experimental methods. With this review, it can be verified that the methods complement each other, thus achieving greater profitability at the industrial level, greater robustness in the design, and facilitating the study of behavior from a thermo-hydraulic approach.