A theoretical study of the heating effectiveness of a composite porous radiant burner (PRB) is conducted. A one-dimensional laminar premixed flame model incorporating a radiatively participating inert porous medium consisting of two layers of different properties is used to describe the heat release/transfer processes. Combined conductive, connective, and radiative heat transfer is considered. The spherical harmonics method with die P-3 approximation is used to model the radiation part. A multistep reaction mechanism for premixed methane-air combustion is employed. A parametric study is carried out to determine the effect of the radiative properties of the two porous layers on burner performance. Calculations indicate that a significant improvement in the radiative output of a PRB can be attained by optimizing the burner properties upstream and downstream of the flame. Generally, the upstream layer should be of lower porosity, shorter length, and higher optical thickness than the downstream layer. Also, the upstream layer should be highly scattering, while the downstream layer should be nonscattering.