Heat production from geothermal reservoirs is controlled by coupled thermo-hydro-mechanical processes and thermal expansion coefficient plays an important role in deciding the fracture aperture. To provide insights on the thermal expansion coefficient values with respect to temperature, two types of sandstones are considered: Remlinger and Flechtinger obtained from Steinbruch, Germany. Measurements are performed with Linseis L75 instrument and the core sample length is 5.26 mm.