Abstract This paper confirms the reliability and the computational efficiency of the lattice Boltzmann method in simulating natural convection in porous media at the representative elementary volume scale. The influence of porous media is considered by introducing the porosity to the equilibrium distribution function and by adding a force term to the evolution equation. The temperature field is simulated by a simplified thermal energy distribution function which neglects the compression work done by the pressure and the viscous heat dissipation. A comprehensive parametric study of natural convective flows is carried out for various values of Rayleigh number, of Darcy number, and of porosity. The comparison of solutions between the present model and earlier studies shows good quantitative agreement for the whole range of Darcy and Rayleigh numbers.