Condensation on the surface of an Air Handling Unit (AHU) can interfere with energy efficiency, air quality and cause damage to the mechanical equipment and building. The fundamental calculation of condensation is complex due to the intricate interaction between the AHU surface and its environment. Realistic modeling of conduction through the AHU walls or roof and convective heat transfer distribution over the AHU surface is crucial to assess to avoid condensation occurrence. The present study investigates thermal bridging effects across the walls or roof of panel joints and condensation occurrence on the AHU surface, considering the effect of thermal insulation, temperature difference, and air velocity. The momentum and heat transfer in the AHU is evaluated using high-resolution 3D steady Reynolds-Averaged Navier-Stokes (RANS) computational heat transfer and fluid dynamics simulations. The airflow inside the unit is considered turbulent forced convection, and the external airflow is assumed natural convection. The conditions for the condensation occurrence are assessed, and a correlation between the thermal and physical properties of the AHU construction and the surface temperature distribution will be developed.