The overheating protection of walls equipped with transparent insulation (TI) usually requires cost intensive, often unreliable mechanical shading devices. An effective way to avoid overheating and simultaneously increase the solar gains is the direct cooling of the outer wall surface (absorber). For this purpose, water is pumped through a system of pipes that is attached to the outer wall surface. The heat transferred to the fluid can be used for hot-water production and/or space heating. Thus, the passive solar TI system is extended to an active/passive solar system, called the transparently insulated hybrid wall (TIHW). In this paper the results of experimental investigations of a laboratory model (aperture 1 m(2)) are presented: more than 75% of the absorbed heat could be removed by the fluid. The surface temperature at the inner wall remains moderate even after a long period of high irradiance. Already with small how rates an effective cooling is achieved. Finally the fast reaction of the system after turning on the fluid pump enhances the control of the TI system in order to avoid overheating in adjacent rooms.