The paper presents the results of an experimental activity aimed at producing and characterizing a nano-encapsulated PEG600 (PCMs) into a silica shell. The nano-encapsulation was meant to be useful to improve the material's suitability to integration in building components. The (300 +/- 15) nm nanoparticles that were produced underwent a full characterization of their thermal performances. An enthalpy of fusion as high as 66.24 kJ/kg, in a tight melting temperature range (20-21 degrees C) was obtained, making the material suitable for thermal energy storage in buildings. In order to demonstrate the benefits of such as this technology on the reduction of heating and cooling demand of buildings, a concentration of 50% in weight of nanoparticles was, then, embedded into a gypsum plasterboard and used for all indoor plastered surfaces of a reference residential buildings. A saving of respectively up to 4.3% and up to 1.1% of heating and cooling energy demand was predicted in comparison to the ones of a building without PCM. Finally, the material underwent a full toxicological characterization exposing human alveolar basal epithelial cells to nanoparticles. The results showed that there were no toxic effects on cell morphology. (C) 2019 Elsevier B.V. All rights reserved.