ZEMCH 2015 - International Conference Proceedings | Page 574

1. Introduction Sustainable refurbishment of existing building stock plays a key role in the energy-efficiency sector, in terms of substantial increase of performance level and real estate value, through significant energy and architectural transformations aimed at achieving nearly Zero-Energy Buildings (nZEBs). Indeed, EU energy policies, EPBD and EED supply wide provisions aimed to increase the energy performance of the existing building stock and to encourage Member States to transform buildings through the development of renovation interventions. At EU level, the energy efficiency and the deep reno vation of the building sector is mainly regulated by two Directives. The Energy Performance of Buildings Directive 2010/31/EU on the energy performance of buildings (EPBD Recast) has significantly affected the redevelopment of legislative aspects for all EU countries. In particular, Article 2 of the EPBD Recast introduces and defines nearly Zero-Energy Building as “a building that has a very high energy performance. The nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby”. The other important Directive is the Energy Efficiency Directive 2012/27/EU on energy efficiency (EED), which requires Member States to develop long-term renovation strategies for their national building stocks, mainly constituted by houses, schools and offices. In particular, Article 1 of the mentioned EED sets out that “the requirements laid down in this Directive are minimum requirements and shall not prevent any Member State from maintaining or introducing more stringent measures” tailored to the different target Regions’ profiles. For the specific Mediterranean context, Nearly-Zero Energy houses should be designed taking into account local climatic factors and technologies able to work effectively both in winter (heating) and - most importantly - in summertime (cooling). Air, sun, water and other climatic factors become essential for the design of a building with high-energy performance, preferably based on the use of local materials and bio-architectural sustainable principles. For the whole Italian building stock, analysis shows that the national annual consumption per unit area (about 250 kWh/m2) is higher than the average amount of other European countries (Energy Efficiency Financial Institutions Group 2015). More than 75% of the buildings belonging to the Italian real estate asset have been designed before 1976, when specific regulations on energy efficiency did not exist yet. It is estimated that for the management of these buildings with inadequate envelopes and very high-energy consumption, a significant reduction up to 50% could be achieved through appropriate redevelopment1. Indeed, refurbishment of the existing building stock represents one of most frequent and complex problems tackled by the construction sector, not only from the functional and architectural point of view, but also for the purpose of energy efficiency. It is always more urgent to outline and disseminate new strategies to tackle the problem of refurbishment of existing stock towards nZEBs, combining innovative materials and technologies, tailored to local building types and to different social/cultural/economic in Italy and in a broader international context. Within the member countries of the European Union, the construction sector contributes on average about 21% to the GDP, creating a high consumption of non-renewable resources and high environmental impact. When viewing the total consumption of these resources, the construction sector annually accounts for the use of more than 40% of non-metal mineral, over 25% of timber, 1 The Green Paper “Towards a European strategy for the security of energy supply” (COM (2002) 321 final) states that at least 22% of energy used in buildings can be saved by intervening on energy efficiency. Further important results are considered achievable with the develop - ment of renewable energy, including its integration into buildings, as shown in White Paper “Energy for the future – renewable sources of energy” (COM (1997) 599 final). 572 ZEMCH 2015 | International Conference | Bari - Lecce, Italy