In order to effectively control the state of an active integrated photonic component based on chalcogenide phase change materials, an efficient microheater operating at low voltage is required. Here, we report on the design of a graphene based microheater. The proposed system contains two separate graphene layers between which the phase change material cell of Ge₂Sb₂Te₅ is placed. Three distinct switching possibilities are explored, using only the bottom layer, only the top layer or both graphene layers. A detailed investigation of the heater parameters is performed to optimise switching performance. A self-consistent multiphysics simulation of the crystallization process in the phase change material cell is conducted demonstrating the switching capabilities of the proposed design.