COMPARATIVE ANALYSIS OF NANOMATERIALS FOR ENERGY EFFICIENCY IMPROVEMENT OF HISTORIC BUILDINGS

The scientific interest in nanomaterials in buildings’’ energy efficiency has increased significantly in the last decade, especially after the application of the ambitious concept of nearly zero-emission building (NZEB). This also leads to an increase of conventional thermal insulation materials’ thickness in order to improve their thermal performance. In some European countries, the thickness of the insulation has almost doubled. This restriction has important economic and technical consequences such as: reduction of internal space, increase of insulation costs and, above all, inadequate change of the original architectural design of existing buildings, i.e. jeopardizing cultural heritage. New buildings have a limited impact on the overall energy reduction because they represent only a small part of the existing building stock. It is estimated that only 1% of Europe annually belongs to the new building stock. Existing buildings therefore represent the greatest opportunity for improvements in energy efficiency. Moreover, new buildings use four to eight times more resources than renovated ones, which is a sustainable argument in favor of renovating existing buildings. The development of high-performance insulation with as low thickness as possible has become a technically and scientifically challenge. Not only the thickness of the material highlights the need for research and development of new materials, but more important factors, especially when it comes to historical buildings. This paper focuses on analyzing nanomaterials for buildings’ energy performance improvement, especially in cultural heritage buildings, whose original architectural appearance should not be compromised during the renovation process. Firstly, extensive literature related to the general application of nanomaterials in the building sector is reviewed, where the most significant properties in terms of their thermal insulation characteristics are emphasized. Then, based on the obtained data, a comparative analysis of the researched nanomaterials was carried out and several criteria were established for the evaluation and selection of the most appropriated materials for historical buildings’ renovation. Finally, conclusions for the selection of nanomaterials with best thermal properties and a minimal impact on the cultural heritage, emerge from the analysis.