This standard sets out a method of determining the performance of a solar water heating system under controlled conditions simulating an average day and a bad weather day.The results obtained under the standard conditions described in this standard may be used for the prediction of system performance under other conditions. Appendix C provides an expression to be used for such predictions.The tests set out do not deal with durability, soundness of construction and safety aspects. The design and construction of solar water heaters with both gas and electric supplementary heating is covered in AS 2712.