Influence of the external air flow rate on the energy efficiency of residential buildings

Ventilation in buildings is an important topic connected not only to indoor air quality and hygrothermal conditions but also for the energy consumptions. Many national and international standards require today high thermal and acoustical insulation of buildings structures, sometimes needing a mechanical ventilation for adequate indoor air quality. In both cases of natural (infiltration) and mechanical ventilation, the related heat transfer gives an important contribution for the evaluation of energy use for space heating and cooling of buildings. In this paper the energy rate due to ventilation heat transfer in buildings with high thermal insulation is analyzed, for different Italian climate with different air flow rate conditions according to national standard. Results are presented according to the calculation model of the EN ISO 13790:2008, where the contribution of other parameters (conduction heat transfer, thermal inertia of structures, etc.) on the global energy performance of building is also analyzed.