Unit of 2 or more panes of glass. Gas filling is used to set thermal transfer properties. Spacer defines the distance between the panes and also accounts for thermal properties. Sealants prevent loss of gas filling and entrance of humidity. Figure 1 shows a sectional drawing of an IGU with the different elements.

Figure 1 – Sectional drawing of an IGU

Key: 1 glass panes 2 primary sealing 3 spacers with desiccant 4 secondary sealing