A detailed experimental and numerical study is carried out to investigate conjugate heat transfer in a horizontal channel with a heated section which simulates Chemical Vapor Deposition (CVD) processing. Since film quality, uniformity and deposition rate have strong dependence on temperature, the role of conjugate heat transfer in influencing temperature distribution is significant in thin film production. Experimental data obtained from this study provides physical insight into conjugate heat transfer effects and allows for comparison and validation of numerical conjugate heat transfer models. The basic characteristics of the flow and the thermal transport are studied. The numerical model is used to perform a parametric study of operational parameters, allowing for the characterization of conjugate heat transfer effects on temperature at the susceptor surface, reactor walls and the gas phase. The study yields valuable guidelines for the thermal design of CVD reactors.