The Portland Cement Association, in conjunction with the Concrete Foundation Association, has released Thermal Mass Comparison of Wall Systems (#CD 026), which proves that insulation and concrete combine well to save energy. Laboratories tested 12 wall systems, including various types of wood frame, steel frame, concrete masonry, insulating concrete forms, aerated autoclaved concrete, and three types of insulated concrete walls, built using re-usable forms--all for the same 2,450-square-foot house. More information is available at