Glazing
In a double glazed insulated glass unit (IGU), there are 2 panes of glass, sealed, with a space in between. This space can either contain air or is argon gas filled for higher performance. The most energy efficient distance in between the glass panes is from 12mm to 20mm. This is set with a spacer.
In a triple glazed insulated glass unit (IGU) there are 3 panes of glass with the middle pane creating 2 spaces, again either filled with air or argon gas. When used with high quality frames, the resulting window can have a U-value, which is reduced to an extremely low 1.1 compared to a single glazed aluminium window of 5.9 – and remember – the lower the U-value, the better the window performance.