The SNUG project addresses the urgent need for Zero Emission Buildings (ZEBs) by developing innovative, AI-driven solutions to improve energy efficiency and sustainability throughout the building lifecycle. Buildings account for 40% of Europe’s energy consumption and 36% of greenhouse gas emissions. However, current renovation rates and efforts are insufficient to achieve climate neutrality by 2050. Therefore, SNUG will develop an AI-based Digital Tool Assistant to optimize the selection of advanced thermal insulation materials and designs, ensuring cost-effective and low-carbon solutions tailored to different building types and climates. Complementing this, sustainable-by-design insulation materials and lightweight prefabricated solutions will leverage circular economy principles, smart materials and renewable resources to reduce embodied emissions. A comprehensive database of insulation materials and a digital building logbook will support informed decision-making and lifecycle monitoring. Real-world demonstrations in three different climates will validate these innovations, showing improvements in energy efficiency, indoor comfort and environmental performance. By enabling tailored retrofits and advancing ZEB standards, SNUG will help to increase renovation rates, reduce energy poverty and contribute to Europe’s decarbonization goals, foster a sustainable construction sector and improve the quality of life for citizens.