This system works along with the grid. This means that any excess or deficiency of power can be fed to the grid through net metering. ... You will always have power either from the solar system or from the grid. They do not have batteries.

This system works independently of the grid but it uses batteries which can store the solar power generated by the system. The system usually consists of solar panels, battery, charge controller, grid box, inverter, mounting structure and balance of systems.

This system is the combination of on grid system and off grid system. It has more then one supply source like solar, grid and batteries.

Flat plate collectors (FPC)- FPCs are the most popular type of collectors. They consist of a rectangular box that is insulated. This box is covered by a glass. Just beneath the glass, there are a series of interconnected copper pipes for the water to flow through. Since it is metallic, this system is more durable.

Evacuated Tube Collectors (ETC)- Evacuated tube collectors employ glass tubes to absorb solar radiations. The core ideology behind this solar hot water system is that vacuum is an effective insulator. A tube called 3T has multiple layers and vacuum is trapped in between them.