The invention relates to a system and a method for insulating a double shell exterior wall. The system comprises an inner shell (1; 101)and an outer shell (2; 102), and mounting anchors (8; 108)being fastened to the inner shell (1; 01) with lateral offsets, and in rows with uniform elevation offsets from one another. The mounting anchors (8; 108) comprise securing means (6; 106). The system further comprises at least one first insulation layer (4; 104) having insulation elements(41, 51; 141, 151), which are supported by the mounting anchors (8; 108) between the inner shell (1; 101) and the outer shell (2; 102).
