Glass industry is one of the most energy and environmental intensive compartments, with high emissions of CO2 both during the production phase and the procurement of raw materials. On top of this, flat glass products are almost never recycled or recovered at the end of their lifecycle, but rather downcycled or conferred to landfill. Several barriers prevent glass from closing its life cycle, from technical to logistical ones. In this study a new closed loop alternative for the architectural glass has been explored. The proposed solution is based on the idea of reusing glass panels coming from building facades, in order to manufacture new Insulated Glass Units (IGUs). The environmental suitability of this options has been evaluated, along with the definition of the necessary quality protocols for the performance assessment of used glass, including safety for its reuse. Forty-three IGUs collected from residential buildings in Belgium have been manually disassembled and their glass panels have been tested with a destructive coaxial double ring (CDR) test. The results show that the mechanical strength of weathered glass is affected more by the surface quality conditions than by any other ageing factors (i.e. lifespan of the IGU, tested face, position of the panel). Furthermore, conclusions on the appropriate conditions and on the equipment for testing the weathered glass can be made.