Split solar heaters give the ability to place the solar collectors and storage cylinders at different levels. In most cases the storage cylinder will be at a lower point than the collectors usually mounted on the floor or ground level.
These systems can be done using either evacuated tubes or flat plate panels and they are nearly always pressurized. As the hot water storage cylinder is at lower level them the panels, active circulation is necessary to ensure water heating takes place. The circulation is achieved by a pumping station integrated in the system. This works through differential temperature control between the collectors and the storage.
They are cost-wise more expensive than both normal evacuated or flat plate systems. They are best suited where installation space is limited or the structure of the existing roof cannot allow certain weights to be placed on it. Weight concerns can arise for instance when installing relatively large centralized systems for hotels and similar institutions. However, split systems are available from a few hundred to several thousand litres.