Solar water heating systems comprise several innovations and mature renewable energy technologies that have been well established for many years. Solar water heating systems use solar panels, called collectors, fitted to your roof. These collect heat from the sun and use it to heat up water which is stored in a hot water cylinder. A boiler or immersion heater can be used as a back-up to heat the water further to reach the temperature you want.
Two principles govern solar thermal collectors. First, any hot object eventually loses its heat back to the environment. The efficiency of a solar thermal collector is directly related to heat loss, mainly from convection and radiation. Thermal insulation is used to slow down heat loss from a hot object to its environment.
Solar water heaters offer long-term benefits that go beyond simple economics. In addition to having free hot water after the system has paid for itself in reduced utility bills, you will be protected from future fuel shortages and price increases. Solar heaters provide additional supplies of hot water for the entire family.
Solar water heaters do not pollute. By investing in one, you will be avoiding carbon dioxide, nitrogen oxides, sulfur dioxide, and the other air pollution and wastes created when your utility generates power or you burn fuel to heat your household water. When a solar water heater replaces an electric water heater, the electricity displaced over 20 years represents more than 50 tons of avoided carbon dioxide emissions alone.