1. Glass is airtight sealed, and many fake hollow glass doors and windows have two pieces of glass glued together with black PVC foam strips, which does not have a sealing effect. The real insulated glass doors and windows are bonded with specialized sealing strips to ensure absolute sealing.

2. There is an aluminum partition strip between two pieces of real insulated glass, and there are many ventilation holes on the aluminum partition strip. Desiccant is placed inside to absorb moisture in the gas and prevent the phenomenon of "fogging" when the glass doors and windows are heated, while fake "insulated" glass does not have these devices. 3. On site testing of the sound insulation effect of doors and windows. The sound insulation effect of real hollow glass doors and windows is very good, while the sound insulation effect of fake "hollow" doors and windows is very average.