This paper aims to evaluate the applicability of a single phase model for heat diffusion phenomena caused by saturated flow through porous media. These were based on laboratory experiments using vertical bead columns. Since permeability of bead column is increased by seepage of hot-water into cold porous media, a new method for the seepage experiment is adopted to fix Darcy velocity. The coefficient of heat diffusion, κ, which is a main parameter of the model was identified from the experimental data. The behavior of κ values under various conditions were investigated and was used as a means of evaluating the single phase model. In this research, it was shown that κ values are linear function of the heat transfer velocity. The relationship between the heat dispersivity β which characterizes κ values, and the spatial scale of flow is also discussed.