A new measuring device for the simultaneous measurement of heat of adsorption and load has been developed. A volumetric adsorption measurement device is extended by a calorimetric unit which measures the pressure difference between two identical sensor gas volumes surrounding a sample cell and a reference cell. Due to the exothermic adsorption a pressure rise in the gas volume around the sample cell is induced. After calibration the heat of adsorption can be calculated from the pressure difference curve. First results of the measurement of the adsorption enthalpy of CO2 on 13X zeolite are shown.