Can polyester fiber acoustic panels provide sound insulation? How much noise can they block?

The primary function of polyester fiber acoustic panels is sound absorption, not sound insulation. If the thickness is 25mm or more, the density is high, and the gaps are sealed during installation, they can reduce some airborne noise, but they cannot block structurally transmitted sound (such as footsteps from upstairs transmitted through the floor). Sound absorption and sound insulation are two different acoustic concepts; please choose the appropriate product based on your actual needs.