Gas into a cavity of a double glazed unit reduces the heat conductance between the panes, therefore helping to keep heat out in the summer and in during the winter.  The thermal insulation is further improved by using a Low Emissivity glass.


The combination of Argon Gas and Low Emissivity glass can achieve a thermal performance of around 50% over that of a standard sealed unit.  The standard gas used is argon krypton can also be used which gives better insulation on smaller cavities.