U values for windows

Formula for calculating the total U value of a window, taking into account the glazing unit, the share of profiles and an edge zone effect linear factor.

Uwindow = ( Ag * Ug + Af * Uf + Ig * ψg )  /  ( Ag + Af )

The links below present tables with the total U value of a window for different glazing units and spacer bar. The calculations should be based on applicable standards and requirements.