This article explores experimentally and numerically the effect of conductance on cooling of electronic chips by forced air flow in a vertical channel for thermal control. Experiments are conducted using substrates of FR4, bakelite, copper clad board (single layer) equipped with aluminum heat sources at uniform heat fluxes of 1000, 2000, and 3000 W/m² at 500≤ Re≤ 1500. Computer simulations are performed to validate experimental results using a finite elements based COMSOL Multiphysics 4.3b software and the results are in agreements of below 10%. The temperature results showed that high thermal conductance copper clad boards (CCBs) are very low in comparison with FR4 and bakelite substrates. Results showed that FR4 and bakelite are unsuitable for airflow velocity of 0.6 m/s and heat flux of 3000 W/m². However, the temperature variation between single and multilayer CCB is 3 to 4 °C. The temperature reduction using CCB is 10 °C compared to FR4 and bakelite.