Mineral stone wool insulation batts are slightly better insulators than the off-the-shelf fiberglass batts sold at most lumberyards and home centers. Mineral wool batts for 2×4 walls have an R ...

Area \(\percent\) heat loss Method How it works Roof 25 Insulate loft with mineral wool or fibre glass. Trapped air between glass or mineral wool fibres reduces heat loss by conduction and convection.