There is currently a lack of a comprehensive energy model for extensive green roof systems. To rectify this, a lumped parameter, one dimensional, time dependent thermal model and subsequent computer program were created to calculate temperature profiles and heat fluxes in extensive green roofs. It was found that varying the plant and soil characteristics did not have a significant effect on the temperature profile of the system. Additionally it was found through a flux analysis that utilizing a green roof produces significant energy savings. The created model allows the user to easily vary all the parameters and model any location.