In Australia, for best performance of solar hot water system should face solar north. The direction can be fixed up to 45°from north without great loss of heating efficiency. For accurate orientation, you could use a compass.
For optimum performance, make sure that the solar water heater is not shaded by any trees or buildings nearby, especially when the sun is low in the sky in winter.
To achieve the most efficiency performance, solar collector need to be placed at an angle to the horizontal. It could reach the maximum sunlight falling on the solar panels of annual amount. It is generally recommended that the installation location of solar collectors installed in the same angle at the latitude angle level. In Australia, this point of view in Darwin in Hobart from 17.5 ° to 53 ° range. In some cases, it may be desirable to increase the angle of improved winter performance and reduce summer overheating.
In practice, many solar water heaters installed in the roof pitch angle, because it is cheaper and often more beautiful and pleasing to the eye installation of solar collectors and the roof flush, instead of using the support to achieve greater angle. The roof angle of inclination in Australia are usually between 20 ° ~ 30 °, which tend to reduce performance in the winter. In the benefits of existing homes will usually outweigh the costs. In the new home, the design of the roof area to accommodate a solar collector angle is possible.