One way to achieve very high levels of insulation in walls is to build two stud walls separated by an air space. The inner wall provides framing for attaching gypsum board; the outer wall does the same for sheathing, a weather barrier, and siding. Two 2x4 framed walls spaced three inches apart will provide a wall cavity about 10 inches deep. This spacing eliminates thermal bridging. When fully insulated, this double-wall thermal blanket creates a quiet, efficient, and comfortable home.