The main goal of ERACLITO is the fabrication of high-quality active photonic crystals (PhCs) whose optical response. The electro-tunable PhC will be based on Earth-abundant and non-toxiccan be tuned by a quasi-static external electric field TCO nanocrystals (NC) and realized by means of large-area-capable fabrication techniques. We will exploit the active PhC for: i) that control transmission of infrared, visible and ultraviolet light through building windows, envisaging a reductionsmart windows of the consumption of energy to regulate the indoor temperature; ii) , that use thermal-emittingphotonic radiative coolers surfaces to radiatively cool through the atmosphere transparency window.