An insulated glass sealed unit is made with two panes of glass which are separated with a spacer frame made from aluminium or foam spacer. The spacer frame is fixed onto the two panes of glass with a primary sealant. A spacer tube is filled with desiccant on two to four sides of the frame (foam spacer is manufactured with a desiccant compound included) and then a secondary sealant is applied to the back of the spacer to seal the unit. Insulated glass sealed units can also be gas filled to improve their thermal efficiency.