Emiliano Carnielo

Preliminary studies of a cool roofs' energy-rating system in Italy

Energy saving in the building sector is one of the key issues to achieve environmental targets at national and European Union (EU) levels. Although characterised by a large number of different climatic conditions, Italy energy policies were aimed at reducing the energy consumption related to space heating in buildings, neglecting space cooling. The recent EU Directive for the State Members is to assess the energy quality of buildings taking into account all the relevant energy uses. Cool roofs are an old concept merged with new technologies that play a crucial role in the energy balance of buildings especially at Mediterranean latitudes. Reducing the solar gains thanks to a high solar reflectance, cool roofs tend to decrease the cooling demand and increase the thermal comfort. Energy rating and labelling are a quick solution to compare energy-related products. This paper presents the first studies aimed at the definition of an energy-rating scheme for cool roofs, starting from product properties and reaching building performances. Energy simulation results were used to find out simple linear regressions, expressing the energy performance of the building as a function of the roofs radiative properties and measuring the performance of the cool roof product.