Inert gas

The inert gases argon or krypton are used to fill the spaces between the panes in double or multiple glazing. The gases achieve an insulation performance around ten per cent better than dried air introduced into the cavity. Krypton is considerably more expensive, but achieves the same insulation performance as argon even at smaller pane spacings, which is why it is used in multiple glazing where the smallest possible frame depth matters. Inert gases also provide a better effect than air in terms of sound insulation.