I'm working in a 1922 house that was renovated in the 1950s. I just finished up the bathroom which had foil faced r11 insulation. I'm getting ready to rip the sheet rock out of the master bedroom because of several layers of wallpaper that have been painted over. I imagine it's the same fiberglass r11 foil faced insulation under there. I replaced it with r15 in the bathroom which was only a 6 foot section. Is the extra insulation worth a few hundred bucks to change in the bedroom or just leave well enough alone?