This paper deals with results of the thermodielectric effect measurement. A paraffin wax as a dielectric material was investigated via differential scanning calorimetry and potentiometry during a phase transition. Possible description of the thermodielectric effect based on fundamental laws of thermodynamics is shown; to be more specific, the link between the potential difference and the latent heat is presented. The thermodynamic model of thermodielectric effect based on electrochemical equilibrium and charge generation at the solid/liquid interface is introduced. Results of the thermodielectric effect measurement are used for the calculation of a molecular mass of the paraffin wax. The relation for a surface area (interface) between liquid and solid phase of the paraffin wax during solidification is derived from the presented theoretical description of the thermodielectric effect.