Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating and due to storage. The storage affects the heat demand passively due to higher temperatures. Hence heat loss is reduced and passive heating is optioned. In theory, by running the system flow backwards, active heating can be achieved.The objective of the report is to present results from measured system evaluation andcalculations in detail. In another report R-007 the main results and recommendations aresummed up for non-technicians. The results of the project are among others: The system is rather simple. Much work can be self-made to keep the price down. The system is working, but heat exchange from plastic piping to sand is rather poor. The dimensioning of the volume is rather difficult based on common knowledge. Passive heating, hence reduction of heat demand, due to the storage and especially due to the oversized solar collector area of the system, was achieved. Active heating from the sand storage was not observed. The pay-back time for the system can be estimated to be similar to solar heated domestic hot water systems in general. A number of minor improvements on the system could be pointed out.