Due to European Union (EU) and worldwide high energy consumption of the buildings stock, it is important to take measures to reduce these needs and, consequently, reduce the EU energy dependency as well as the greenhouse gas emissions. To improve the behaviour of the buildings, concerning thermal comfort of the occupants and energy performance, it is necessary to use thermal insulation and the buildings thermal inertia, to reduce the thermal amplitudes, the winter heat losses, the summer heat gains and to store the energy from solar gains [1, 2]. The use of phase change materials (PCM) in the buildings is a possibility to achieve this as it allows the use of latent heat storage to increase the thermal inertia without significantly increasing the building weight