Optimizing Sound Insulation Performance of Triple Glazing with Different Glass and Cavity Thickness Combinations

Triple glazing has garnered widespread attention as a key solution that balances sound insulation, building energy efficiency, and thickness-related cost-effectiveness. This study evaluated the acoustic performance of triple glazing, focusing on how cavity and glass thickness combinations performed under a fixed total thickness. Laboratory measurements were first conducted, which revealed that asymmetric triple glazing performed better for sound insulation than symmetric combinations. Based on this, 28 triple glazing combinations with a total thickness of 42 mm were selected to build finite element models, including window frames. These models were used to calculate the sound transmission loss curves, the weighted sound reduction index, and the distributions of structural stress and the displacement amplitude. The best sound insulation performance was achieved when the glass panes had unequal thicknesses, with the thickest pane positioned on the outermost layer (either on the source or the receiver side). The weighted sound reduction index Rw increased by 6 dB, and the combined value of Rw and the traffic noise spectrum correction (Rw + Ctr) improved by up to 11 dB. The optimal combination was 8-12A-6-12A-4, and Rw reached 44 dB. Combinations with the thickest pane in the middle layer or with equal pane thicknesses exhibited a worse sound insulation performance. Variations in the cavity thickness had a smaller effect on sound insulation than changes in the glass’s thickness. A reasonable combination of glass thicknesses in triple glazing effectively reduced the displacement amplitude and improved the sound insulation performance.