As the air-side heat transfer is controlling the efficiency of fin and tube heat exchangers (FTHX), the thermal enhancement of FTHX relies more on the air-side. A theoretical model of the baseline FTHX is built using ANSYS Fluent which is then validated by wind tunnel experiments. After analysing the simulation results of the baseline FTHX, two novel air-side fin configurations are proposed. The first design can guide more airflow to the back of the tubes to mitigate wake zones. For the second design, topology optimisation is used to significantly increase the heat transfer area at the air-side with minimised pressure drop penalty. To further improve the two designs, parametric studies are conducted through which optimal design parameters are obtained. Comparing with the baseline FTHX, the optimal guiding channel fin design and topology optimisation fin design can dissipate 8.5% and 7.0% more heat respectively, or consume 41.4% and 33.3% less fan power respectively. As such, the proposed enhanced air-side fin designs are promising candidates for improving the efficiency of FTHXs. (C) 2018 Published by Elsevier Ltd.