Abstract: An insulated glass unit formed from a pair of glass sheets, one of which has an electroconductive coating, i.e. a first sheet, is fabricated by positioning the first sheet on a vacuum support and the other sheet, i.e. second sheet, spaced above the first sheet a sufficient distance therefrom to prevent arcing during electrical heating of the marginal edges of the second sheet. After the marginal edges of the second sheet are heated to a temperature sufficient to cause sagging of the marginal edges, the two sheets are brought together to join the marginal edges by fusion. A strip heater heats the edges of the sheet to a temperature sufficient to prevent chilling of the marginal edges of the upper sheet when contacting the marginal edges of the lower sheet. Thereafter, the sheets are separated from one another and air moved between the sheets to bloom the edes. After blooming the edges, the joined glass sheets are annealed, and an insulating gas moved into the airspace through a pore hole.