A system provides insulation products for a plurality of insulation wall cavities in buildings, where a substantial portion of the insulation wall cavities have a known nominal width. The system includes providing flangeless insulation products having a blanket of fibrous insulation material and having a facing material with a width substantially equal to the width of the insulation blanket, with the width of the insulation blanket and the width of the facing material being greater than the nominal width of the plurality of insulation cavities. The increased width of the facing material improves the seal of the facing material when the insulation product is placed within insulation wall cavities of the known nominal width in comparison to the seal provided by flanged insulation products applied with inset stapling to the same insulation wall cavities.