Energy Savings in Buildings: A Global Approach

Abstract

The present paper reports a set of considerations and analysis of energy efficiency in buildings by approaching the problem from a full life-cycle perspective. In particular, the impact of the embodied energy, i.e. the energy necessary to produce a specific material, is analyzed, as it has a pivotal role in assessing the real energy saving obtained after a retrofitting. Considerations related to the country of production of insulating materials are also provided, as the energy mix of a specific location has an impact on the embodied energy of the materials. Finally, some numerical examples are provided in three Italian cities, namely Milan, Rome and Naples. A typical Italian building is considered in all of these three locations and a refurbishing intervention is hypothesized, namely the installation of an external insulation layer on the walls. Then, the global heating energy saving is assessed, i.e. also the embodied energy is considered in the calculation, to evaluate the energy effectiveness of the intervention. It is found that in warmer locations, i.e. Naples and Rome, the installation of an insulation layer has a limited, or even negative impact, on the energy saving if embodied energy is considered. This means that the energy necessary to produce the insulating material is higher than the energy saved during its operating life.