Prefabricated insulation envelope system on facades. Enclosure system (4) in prefabricated insulation on facades, comprising panels (6) insulating and self-supporting in a polygonal shape, with assembly means and, positioning means, where each panel (6) comprises a first layer (1) of support, a second layer (2) of insulation on the above, a third outer layer (3) on the second layer (2), and fixing means to the facade formed by at least one fixing anchor (7) in each corner of the panel (6), where each fixing anchor (7) has a first end (7.1) suitable for fastening to the faºade and a second end (7.2) suitable for coupling to the panel (6). (Machine-translation by Google Translate, not legally binding)