abstract
The main goal of the EPBD (Energy Performance Buildings Directive) is the improvement of the energy
performance of the European buildings. The internal comfort is critically dependent on the envelope that
plays a key role in the thermal balance of the entire building. In particular, the windows are one of the
most critical elements in terms of solar gains, heat losses and thermal bridges; therefore, the design of
high efficiency frames is requested, both in cold and warm climate, but with different peculiarity. The
UNI EN ISO 10077-2 provides a methodology to evaluate the frame thermal behaviour and it proposes
the criteria to validate the numerical model.
