Background Construction is the single largest activity and industrial employer in Europe. In addition, the greatest energy saving potential lies in buildings. However, sustainability in the building sector must be assessed over the whole life cycle for all building components and materials. Housing has been identified as one of the three areas of consumption (together with food and drink, and private transportation) that are responsible for 70-80% of the whole life-cycle impact of products. In Mediterranean regions, the solar radiation in summer can cause overheating of the building envelope (roof and walls) and the indoor environment, entailing the need for air-conditioning. Passive systems to limit solar effect mainly consist of ventilated facades and roofs as the element which is most exposed to solar radiation. Vented roofs can greatly reduce heat due to solar radiation, but their performance is highly dependent on roof exposure and, more importantly, their perpendicular position to the wind. The benefit of so-called ‘above sheathing ventilation’ (ASV) significantly decreases when the wind direction shifts from perpendicular to parallel to the eaves line. ASV positively affects thermal insulation thanks to convective heat transfer. Buoyancy-driven ventilation becomes irrelevant even with a very weak wind, while the air permeability of tiles determines an increase in performance. Thus, roof tile vents could be considered the best solution for passive thermal insulation for buildings in hot and mild climates. Objectives The LIFE HEROTILE project aims to design and produce two types of roof tiles (Marseille and Portuguese roof tiles, which cover more than 60% of pitched roofs in Europe) with a shape characterised by higher air permeability through the overlap of the tiles and improved energy performance through under-tile ventilation. An air inlet will greatly increase the inflow of air and therefore the heat disposal. In addition, the tile design will be independent of wind direction, since the inlet and outlet channels will let the air flow horizontally as well as top to bottom. The tiles will be tested on real-scale buildings with seven different roof types and located in different Mediterranean regions. The project’s ultimate aim is to demonstrate that the designed tiles can help save up to 50% of the energy for cooling buildings. According to these estimates, the technology – if widely adopted in the Mediterranean countries – could generate savings between 5 000 and 13 000 GWh of electricity per year, avoiding emissions of 1.5-3 million equivalent tons of CO2. Expected results: The project expects to achieve: A 50% reduction of energy consumption for cooling, equal to a value of 2.3 W/m3; A 50% reduction of equivalent thermal transmittance of a vented roof (equivalent U-value), equal to 0.25 W/(m2 K); A 25% reduction of maximum under-tile air temperature; A 30% increase under-tile yearly average air velocity; A 50% reduction under-tile maximum radiation; A 50% reduction of carbon footprint with regard to building cooling applications in comparison with a standard pitched roof; A five per cent reduction of electricity consumption for air conditioning in urban areas, equal to 25 kW/ha; A 10% reduction of greenhouse gas emissions (considering Mediterranean EU countries cooling demand) up to 1.5 Mt CO2/year; and A five per cent reduction of air pollution (considering cooling demand Mediterranean EU countries), up to 0.1 Mt PM2.5/year and of 1.0 Mt NOx/year.