How does solar thermal work?

A solar thermal system captures heat from the sun and uses it to pre-heat cold water before it flows into your hot water tank.  Solar energy, in the form of heat, is collected by flat plate or evacuated tube solar collectors.  A pump circulates a transfer fluid through the collectors absorbing the heat from by the sun.  The heated transfer fluid moves through piping down to a heat exchanger at the solar hot water tank where the hot water is stored until you use it.  The solar thermal system will work throughout the year, although the energy available reaches its peak in the summer.  The system is freeze protected and will become your primary source of hot water, while your existing electric, natural gas, propane or oil hot water heater functions as a backup system.