Transmittances

It is measured in W/m2K and it gives the measure of thermal insulation provided by a window. From the physical point of view it expresses the amount of heat that escapes through the window.
To have windows with low thermal transmittance values is useful during the winter as the heat losses of heated rooms to the outside or to unheated rooms are limited. Windows with low thermal transmittance are also useful in the summer to prevent the overheating of the living spaces and possibly to decrease the overload on the thermal conditioning system. The simplified calculation method of the thermal transmittance of the window that we use is that one provided by the UNI EN ISO 10077-1. This methodology allows to evaluate the thermal performance of the windows in their entirety from thermal performance of the frame and glazing. In any case, the new windows and existing windows with new panes should respect certain transmittance limits defined in function of the belonging climate zone of the municipality where the building object of the intervention is located.