Solar water heating or solar hot water is water heated by the use of solar energy. 

Solar heating systems are generally composed 

• solar thermal collectors
• a water storage tank or another point of usage
• interconnecting pipes 
• a fluid system to move the heat from the collector to the tank

A solar water heating system may use electricity for pumping the fluid, and have a reservoir or tank for heat storage and subsequent use. The water can be heated for a wide variety of uses, including commercial, business and industrial uses. 

Heating swimming pools, underfloor heating or energy input for space heating or cooling are common examples of solar water heating. A solar water heating system can form part of a solar thermal cooling system, promoting efficient temperature control of buildings or parts thereof.