Evaluation of the Energy and Environmental Payback Time for a NZEB Building

The building sector is responsible for a significant share of the global energy consumptions and emissions in the European Union. In order to reduce both greenhouse gas emissions and primary energy consumptions different energy efficiency measures have been promoted mainly focusing on the reduction of the impacts connected to the operational phase of the building. For example, the EPBD Directive of the UE Parliament imposes from the year 2021 the NZEB standard for new buildings. This goal implies the integration of extra materials and systems in new buildings and consequently the increase of embodied energy and carbon, shifting burdens from the operational phase to the construction one. This paper aims at studying the environmental payback periods linked to the increase of the energy performances of buildings from the current Italian law standard to the NZEB standard. An ideal cubic building case study is defined and the influence of its location is analyzed considering three different Italian cities: Turin, Rome and Palermo. The results show that the payback periods are much lower than the useful life of the buildings confirming the important role of NZEB in addressing climate change and energy saving.