Photovoltaic (PV) modules and solar thermal collectors are convectional solar systems that convert solar radiation into electricity and heat energy respectively. PV modules generate clean electricity and ideal for use in developing countries where human settlement is scattered in remote rural areas and no grid electricity is available. However, electrical conversion efficiency of commercial PV modules is still low (~20%) hence about 80% of the incoming solar energy is lost as waste heat which raises module temperature resulting into a reduction in its electrical efficiency. Hybrid photovoltaic/thermal (PV/T) solar collectors are innovative systems that generates heat and electricity simultaneously hence increases solar energy conversion efficiency of a PV module. A PV/T system is a PV module with a heat exchanger attached behind it for passing a colder fluid (usually air or water) for extracting useful heat and hence cooling the PV module. In the present work, a parametric model based on heat transfer between adjacent components of a PV/T air collector under natural flow was developed. The model was coded in FORTRAN 95 and validated from experimental data measured on a similar experimental model. The validated model was used to study theoretically the effects of some design and operating parameters on the channel wall heat flux. The results show that increasing thermal conductivity of tedlar increases the heat flux transferred from the two channel walls while increasing the thickness of the back EVA decreases the heat flux transferred from the two walls to airflow.