Achieving EU’s energy-efficiency targets (2050 goals) depends on the right measures to retrofit existing building stock, which is dominated by residential buildings. Approximately 85% of the existing dwellings were built before 1990 with poor façade and roof insulation. Due to this weakness much energy is wasted when operating auxiliary heating, ventilation and air conditioning installations. Current retrofitting attempts by increasing envelope thickness bring negative consequences like too high airtightness, over-heating, poor ventilation and loss of space due to voluminous retrofit units.ADAPTIWALL solves this problem by using nanotechnology to develop a multifunctional and climate-adaptive panel for energy-efficient buildings. This novel panel consists of 3 elements: 1) lightweight concrete with nanoadditives for efficient thermal storage and load bearing capacity; 2) adaptable polymer materials for switchable thermal resistance; and 3) total heat exchanger with nanostructured membrane for temperature, moisture and anti-bacterial control.ADAPTIWALL panel is innovative due to its lightweight design and quick low-cost installation; switchable thermal resistance for heat exchange and storage; highly improved energy efficiency; and suitability to be used for façade or roof in cost-efficient retrofitting and new buildings in different European climate regions. When used for façades, ADAPTIWALL panels reduce the building’s energy consumption by more than 50% in comparison with conventional retrofitting. Their ventilation and heat exchange properties significantly contribute to create a healthy and comfortable indoor climate, while eliminating the need for auxiliary installations.The ADAPTIWALL research project focuses on developing adaptive (nano)materials; applying the materials in a lightweight panel; enhancing the panel’s structural, fire safety and sound insulation properties; and demonstrating the novel prefabricating systems to European construction industry.