A process is for insulating an appliance, in particular a three-dimensional appliance likely in particular to be exposed to high temperatures, such as a domestic oven. The appliance has one or more internal spaces to be insulated. Flakes and/or nodules of wool(s) and/or fibers, in particular mineral wool(s) and/or fibers, are blown into the space(s) to be insulated without adding binder or water.