Abstract: A method for fabricating a plurality of insulating glass assemblies, the method comprising the steps of providing a plurality of glass assemblies each including a pair of generally parallel, spaced glass panes having therebetween an endless spacer, the spacer and the panes defining an interior space between the panes and inside the spacer, and the spacer having therethrough a tortuous passage affording gas flow into and out of the space, placing the glass assemblies in a chamber, creating a vacuum in the chamber so as to remove substantially all of the air from the spaces, introducing into the chamber a gas having a coefficient of thermal conductivity lower than that of air so that the gas fills the spaces, removing the glass assemblies from the chamber, and closing the passages in the spacers.