Abstract: A system and a method for in-line production of insulated glass units (IGU) for custom windows. The system and method schedule IGU production based on the order in which the cut glass is available, or broken out, from a glass cutting station. Once the IGUs are assembled, they are then sorted into the order in which they are to be further processed, i.e., into the order in which the corresponding windows are to be produced and shipped. Thus, the sorting, or carting, step occurs after the cut glass is contained in sealed IGUs, and the workers who perform the sorting step do not have to directly handle the pieces of cut glass.