Double-glazing is widely used in constructions due of their sound insulation performance. According to the standards, the prediction of their acoustic performances is carried out in laboratory using two reverberant rooms. It's well known that, in the low frequency range below the Schroeder frequency, the presence of these rooms can affect the measurements due to their modal behavior. Thus, the prediction of their acoustic and vibratory behavior is very complicated and depends on several factors such as the used materials, the boundary conditions and the diffuseness of the acoustic field. In this work, experimental and numerical studies on the vibroacoustic behavior in low frequency range of double-glazing are presented. First, a finite element model for the proposed fluid-structure coupled problem is proposed. Experimental modal analysis of the structure is then detailed. The results of this analysis are used to validate a numerical model of double-glazing. Finally, various models for numerical sound reduction prediction of double glazing are presented and compared.