The market for small solar combisystems has so far stayed way behind its huge potential. One of the reason may be that the quality and the thermal efficiency of the systems installed in the field is often lower than expected. Compact prefabricated systems have the potential to substantially reduce the effort and cost for their installation. Nevertheless, thermal efficiency should be clearly evaluated by lab testing. Until now it has been difficult to determine an accurate performance rating for those systems, and even more difficult to compare them, because there were no common definitions of terms for that type of system. For the development of the market of compact pre-fabricated solar combisystems, the existence of uniform test methods, recognized by the whole solar industry, is important. As a first step towards this goal, this paper give an overview of the information given to the manufacturer by these methods in term of thermal efficiency and knowledge of their product. The objective of the complete system test is to evaluate the thermal efficiency of complete systems including storage, controller, auxiliary boiler, pumps, valves, etc., in the laboratory thanks to a semi-virtual approach where climate, collector field, building and domestic hot water draw off are emulated. Based on this, three different test methods lasting 6 to 12 days have been developed and successfully applied to a number of small compact solar combisystems. Unlike field tests that need much more time to show the behaviour and performance of a system for a whole year, this kind of test method produces comparable results within a few weeks. The whole system test reveals unexpected behaviour of the systems in most cases and in some cases this behaviour was also detrimental to the system performance. The manufacturers like this kind of test method not only for getting independent test results that show the potential of their system, but also for testing prototypes prior to market introduction. This can be explained by the fact that this kind of test gives reliable function control and performance data within a few weeks. This data is more detailed and has a higher accuracy than what the manufacturer can expect from a whole year of field test monitoring. The test methods are suited for the determination of the annual performance of solar combisystems, including also a full evaluation of their functions and interactions.