Solar thermal works by passing an oil/water fluid through solar collectors on your roof where the sun heats the fluid. The fluid is then pumped around a sealed circuit and into a coil within a specially designed hot water cylinder which heats the water for use in your central heating system or as hot water.
A solar thermal system should provide all the hot water you need in the summer and a good proportion during the winter.
A solar thermal system will heat water for free, therefore reducing your energy bills as well as reducing the carbon footprint of your home.