A method for preparing an insulating product based on wool includes an aeration step inside a device, the device including a chamber and at least one structure capable of generating a turbulent gaseous flow, during the aeration step. A stream of carrier gas is introduced into the chamber and a wool in the form of nodules or flakes is subjected to the turbulent flow of this carrier gas with entrainment in one sense in a direction A and in the opposite sense in a direction B that is the opposite to the direction A so that within the chamber there is at least in one plane perpendicular to the direction A in which the wool entrained in the direction A crosses the wool entrained in the direction B.