Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Only a minuscule fraction of the available solar energy is used.Solar energy's uses are limited only by human ingenuity. To harvest the solar energy, the most common way is to use solar panels.

Solar heater is water heated by the use of solar energy. Its system may use electricity for pumping the fluid, and have a reservoir or tank for heat storage and subsequent use.A solar heater system can form part of a solar thermal cooling system, promoting efficient temperature control of buildings or parts thereof.