In the 1970's when the Swedish development seriously started, experimental plants were built with the primary aim of testing various technologies. The economical aspects were of secondary interest which, in many cases, resulted in high costs and even in poor quality. In the second plant generation during the 1980's, R & D was concentrated upon lowering costs and enhancing performances for the most promising system concepts. Systems are included here for DHW, and for combined DHW and space heating designed for solar heat coverages between 30% and 80% of the annual heat requirement.In the named plan, the state of the art and the R&D needs are described with the focus upon residential heating . Included are systems for multi -family houses, incorporatin groof-integrated solar collectors and short-term heat storage. More developed construction and urban planning methods for roof integration is stressed here, as well as systems flexible for size expansion, e.g. throug connection to an external seasonal heat storage.Also included are district heating systems for solar heat supply of upto a couple of hundred flats . Ground or roof based collectors and seasonal heat storage in water-filled pits or ducts in deep ground are considered here . Emphasis is placed on more efficient high temperature flatplate collectors, more simple piping systems and further development of heat insulation and water-sealing methods for pit storage as well as high temperature practical tests for duct storage.