Solar water heating systems, or solar thermal systems, use free heat from the sun to warm water. A conventional boiler or immersion heater can be used to make the water hotter, or to provide hot water when solar energy is unavailable. The hot water can be used throughout your home for bathing, showering and your hot taps.
Solar water heating systems use solar panels, called collectors, fitted to your roof. These collectors are filled with a special fluid, typically a mix of water and glycol (anti-freeze), which absorb heat from the sun and use it to heat up water stored in a hot water cylinder.
A boiler or immersion heater can be used as a backup to heat the water further to reach the temperature you need.