Carrying out experiments in tunnel kilns are difficult and costly. Due to the large length of such kilns that sometimes reaches 180 meters. That causes the production cycle takes some days. Therefore, a mathematical model is needed to simulate the heat transfer process in such kilns. In this contribution, a simple shape product (vitrified clay pipes) was used in the modeling, in order to simplify the complexity of the process. The bvp4c code was used to solve all ordinary differential equations (ODEs) of the model to obtain temperature profiles of the system using Matlab. Results revealed that: the excess air number has a higher impact on the heat transfer process inside the kiln. Consequently, the thermal heating of products could be easily controlled, by changing the excess air values. Heat transfer coefficient enhancement is a key parameter to save the energy consumption within the kiln.