Materials properties like hydriding enthalpy, heat capacity and volume dilation are essential for modelling and designing of metal hydride processes. The hydriding enthalpy and the heat capacity are calculated from an overall energy balance. A reaction calorimeter has been built up, and the overall energy balance has been derived. All energy terms are calculated and compared with the energy production caused by the hydrogen storing in the alloy. It will be shown that it is justified to neglect a couple of terms to simplify the energy balance.