The Benefits of Double Glazing. Double glazing quite simply means two panes instead of one. Modern double glazing commonly has a gap of 16mm between the panes and often an inert gas such as Argon, Xenon or Krypton sandwiched between the two panes. http://www.andindi.it/index.php?option=com_k2&view=itemlist&task=user&id=909175