In the present work, the thermal contact resistance in a double fin-and-tube heat exchanger is investigated using multiphysics numerical approach. A three-dimensional (3D) Computational Fluid Dynamic (CFD) model is constructed in commercial software COMSOL Multiphysics® by coupling steady-state conjugate heat transfer and turbulent fluid flow. The impact of contact resistance at the fin and tube interface is analyzed by quantitatively evaluating the thermal-hydraulic characteristics. It is found that contact resistance of 3.3 × 106 Km2/W can reduce the overall performance by approximately 6% when compared without thermal resistance at the contact interface. The developed model can predict the effectiveness of the fin-and-tube heat exchanger design with or without thermal contact resistances. Furthermore, the model can be employed to improve the overall heat exchanger performance used in various applications. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.