Energy surveys for sustainable retrofit of existing residential buildings

Directive 2002/91/EC made energy certification for buildings compulsory in every EU member state. To provide valid certification it is fundamental to assess the energy performance of new and existing buildings. In the latter case, the assessment is necessary also to foresee all possible retrofit strategies. To carry out a correct survey it is indispensable to measure the performances of opaque and transparent components of the envelope, consumptions of HVAC services and the evaluation of thermal comfort inside the buildings. For these reasons, the authors have developed a methodology for energy surveys of existing buildings and experimented it in several test cases for over a year. The methodology includes the use of instruments such as heat flux meters, IR cameras and microclimatic data loggers. To reach this goal, it was first necessary to adapt international measurement standards to Mediterranean climatic conditions (especially for the measures of thermal transmittance). Then a survey method was set up and tested on several existing residential buildings. The study cases were chosen basically from among traditional Sardinian houses made of earth bricks and more recent lowcost housing. The outcome of the research is firstly the proposal of an integrated assessment method for energy performances of residential buildings, one that includes the use of different measurement instruments, and which is the basis for correct certification. The research is also the starting point from which to propose different examples of possible retrofitting strategies on existing buildings, both traditional and modern, and their economic advantages.