Cold water from the home’s regular water line is pumped to the roof where it enters the thermal energy collector. Sunlight strikes the collector, and the sun’s heat warms the water. The heated water then comes back into the home or business inside. Inside, the warmed water from the roof is collected in a “solar” holding tank, which has temperature sensors and other mechanisms. The warm water from the solar system then goes into the regular hot water system. Because the regular hot water system (either electric or gas heated) is heating warmer water, you don’t have to heat it as much as if it were plain cold water. If no one turns on a hot water tap, the water is circulated back to the roof to be heated even more. During the night, the system can be set up so that water is not pumped to the roof, preventing heat loss to the cool outside air.
Solar hot water heating systems are generally composed of Solar Thermal Systems collectors, a fluid system to move the heat from the collector to its point of usage, and a reservoir or tank for heat storage and subsequent use. The systems may be used to heat domestic hot water or swimming pool water. The solar heating system can reduce hot water consumption by up to 90%!