What is Uw?
Heat transfer coefficients of the window component including glazing are usually calculated according to DIN 10077-1.
Uw = U window – the U value of the entire window It includes the values for the window frame and the glazing.
A low U-value for windows and doors is particularly important because it allows energy costs to be saved. If you pay attention to the different insulation values of materials and their optimum composition when you buy them, you can save yourself the annoying extra costs for heating later on.