We will validate an affordable (28% reduction of total costs) and lightweight (35% weight reduction) solution for envelope insulation to bring existing curtain wall buildings to “nearly zero energy” standards while complying with the structural limits of the original building structure and national building codes. Two key commercial insulating products:• Highly insulating mono-component and environmentally friendly spray foam, EENSULATE foam, for the cost-effective automated manufacturing and insulation of the opaque components of curtain walls as well as for the significant reduction of thermal bridges during installation (SELENA and EVONIK in cooperation with ULSTER);• Lightweight and thin double pane vacuum glass, EENSULATE glass, for the insulation of the transparent component of curtain walls, manufactured through an innovative low temperature process using polymeric flexible adhesives and distributed getter technology, thus allowing to use both annealed and tempered glass as well as low emissivity coatings (AGC, SAES and TVITEC in cooperation with ULSTER and UNIVPM ). A multi-functional thermo-tunable coating will allow for dynamic solar gain control as well as anti-fogging and self-cleaning properties (AGC in cooperation with UCL).They will enable insulating solutions that Focchi, DAPP and Unstudio will promote with two different levels of performance:• EENSULATE Basic curtain wall modules where the thermal and acoustic insulation will be provided by the novel EENSULATE glass and EENSULATE foam in the spandrel combined with state of the art low-e coated glass;• EENSULATE Premium modules integrating the thermo-chromic coated glass with additional self-cleaning and anti-fogging functionalities. BGTEC will exploit the limited thickness and high insulating properties of the EENSULATE glass to introduce in their range innovative solutions for the fenestration challenges in historical buildings, compatible with the original window frames and sash designs.