ComfortBatt is a stone wool exterior wall insulation that offers thermal protection, fire resistance, and water repellency. Made from natural basalt rock and recycled slag, it provides thermal resistance up to R23 for 2x6 construction, can withstand temperatures up to 2150 degrees F, and will not rot, corrode, absorb water, or promote mold growth. Cost: $30 to $35 per bag. Roxul. 800-265-6878.