Today, our society has the duty of reducing the energy consumed in the building sector. A promising technology to achieve this goal is the implementation of thermal energy storage (TES) solutions in buildings envelope. Lately, much literature dealing with the effect of the inclusion of latent heat storage materials in construction materials to provide higher thermal inertia has appeared, mostly focusing on the evaluation of the thermal properties, density, or porosity of these new materials. However, few of them evaluated the long stability properties of the materials with embedded PCM when included in a building, very much needed since the lifetime of a building is about 50 years. Therefore, in this study, an evaluation of a house-like cubicle of concrete with micro-encapsulated PCM after a decade of its construction is carried out. The results are compared to the tests done in 2005 concluding that the thermal performance of this cubicle presented no degradation in the PCM effect.