An enclosure is made out of transparent or translucent panes which form a chamber (1) through which a liquid flows in closed circuit and which interchanges energy with the inner and outer environments, a heat exchanger (2) in contact with the liquid, a circulation pump (3), and a hydrostatic pressure reducer device (4). The hydrostatic pressure reducer device allows the reduction of the thicknesses of the transparent panes which hold the liquid inside. The active character of the enclosure is due to its capacity of controlling the solar heat load and the illumination. The solar heat load is regulated through the heat exchanger. The illumination of the building is controlled through the adjustable transparency of the liquid. The described enclosure allows the creation of an isothermal envelope which allows the climatization of the building. The system can be used for active outer enclosures or for interior partitions for the climatization and luminic control, as well as for glass roofs or false ceilings.