Accredited calculation of thermal transmittance of windows, doors and shutter boxes

The standard allows for the following outputs:

• Thermal transmittance of single windows, coupled windows and double windows,
• Thermal transmittance of windows with closed shutters or external blinds,
• Thermal transmittance of doors, both glazed or with opaque panels,
• Thermal transmittance of window and door frames, Uf
• Linear thermal transmittance of the joint of frames with glazing or opaque panels,𝜓
• Thermal transmittance of roller shutter boxes, Usb

The mentioned parameters are determined by means of steady-state finite element analysis or analytical calculations. As input data, the geometry of the object under analysis and the thermal performance of all materials or components comprising it are required.

If finite-element calculations are used, it is also possible to visualize the temperature profile and heat flow distribution in the component under analysis. This offers the possibility of recognizing any weak points from a thermal point of view and identifying possible improvements.

This applies equally to new windows as well as to windows in existing buildings - and can be particularly interesting when it comes to renovating historical windows to improve their thermal performance and to prove their energy efficiency for funding programmes.