The U-Value is used do indicate the heat transfer of a construction unit or their components (wall, roof, window, profiles, glass etc.). The U-value has to be determined according to European harmonized standards since the introduction of the energy economizing regulation 02-01-2002. As manufacturer of window and frame profiles we are obligated to fix the Uf-values for the profiles or profile combinations.
The values are determined by measurements in accordance with EN 12 412-2 or calculations in accordance with EN ISO 10 077-2. In order to avoid to measure or calculate each profile combination possible in a system procedures are fixed in the ift Rosenheim guidelines WA-01/1 and WA-03/1 for the definition of system-dependent curves, from which the Uf-values for window profiles can be derived by the relationship between height of the insulating zone(s) bt and total elevation width B and for facade profiles by the room-side profile depth lf.
These curves are based either on official test reports of ift Rosenheim or on own calculations, according to applicable standards.
Download thermal parameters (PDF-file/3.693 KB)
For accurate calculation of the U-value you can use our software HUECK TEC or an Excel Worksheet, which we put to our customer free of charge at the disposal. Orders and further information at
