Abstract: The solar installation (10) according to the invention having a collector array (K) and a heat storage container (20) has a drain-back holding device (24) which is integrated with a heat exchanger (22), which is located in the container (20), in that its upper area has an expansion and return volume. It is preferably in the form of an integral pipe coil (R), which is a smooth-pipe helix with a uniform gradient. Furthermore, a second heat exchanger (34) can be arranged, coaxially with respect to it. The pipe coil (R) has means, at least in the lower area, for reducing the free flow cross section in the pipe interior (32), specifically cylindrical or profiled, fixed or moving filling bodies (30) which, for example, are individual bodies, which are closed at the end, with a standard form which promotes swirling, and/or which may be composed of a material of high thermal capacity, such as steel, stone, ceramic or the like.