High level circular use of post-consumer insulating glass units will contribute to lower the environmental and social impact of insulation glass industry. The application of various circular strategies for insulating glass units (IGU’s) is rising. The product age will give an indication of the remaining life-time of an IGU, but a method which includes screening a technical quality is needed to check if an IGU is indeed suitable for re-use on a high level of circularity. In this study the argon concentration is suggested as discriminative quality. Energy efficient double glazing applied in windows of buildings situated in The Netherlands were studied. Product codes were noted and unraveled. Measurements were performed using the Sparklike Laser Portable, a non-invasive argon measuring device, which generates argon concentration, glass thickness and cavity width values. In addition, measurements were performed with a Glass Check thickness meter. The resulting data were analyzed. Measuring errors were explored and used to setup a testing procedure. Threshold values of the product age and argon concentration were selected for different circular strategies. In conclusion, a screening method using the product age and argon concentration to determine the circular use potential of insulating glass units is proposed.