We investigated free convective heat transfer within an electronics cooling system with a metallic porous extension. The finite element method is used to solve the associated transport equations. Changing fluidic and geometric parameters allows examination of the isotherm contour, streamlines, and heater average temperature. It is found that the presence of a metallic porous block causes higher temperature up to a greater height of the domain than the absence of a porous material. The strength of the vortex is greater in the case of porous extension than in the case of no extension. Furthermore, the effect of Darcy number (Da) on average heater temperature (θavg) is negligible. The value of θavg decreases as the height of the porous extension increases. Inferences obtained from this analysis are expected to provide an adequate basis for the effective design of small-scale thermal management devices/systems that are typically used in electronic cooling systems.