On the influence of the air infiltration heat losses on the energy performance of Italian residential buildings

It is often discussed about the possibilities that more efficient windows offer to reduce the energy loads in residential buildings. Often such results can be achieved reducing the thermal transmittance or optimising the solar gains, not so often the influence of the air permeability is taken into account. This issue is, on the contrary, very important in countries, as Italy, where the age of the building stock is accompanied by the installation of very old windows, characterised by high air leakage, which causes strong heat losses and discomfort phenomena for users. This paper aims at giving an idea of the achievable heating energy savings coming from the application of more tight fenestration systems at national and dwelling level. This should give also some useful indication for users about the economic savings that can be obtained during the life cycle of the installed product. It is also presented the ENEA experimental building, where testing and evaluation of different fenestration products, concerning the energy and the thermal comfort performances, are scheduled for the next heating season