Solar hot water heaters use the sun to heat either
Solar hot water heaters use the sun to heat either water or a heat-transfer fluid in collectors. There are passive systems and active systems. A typical system will reduce the need for conventional water heating by about two-thirds. Sometimes the plumbing from a solar heater connects to a house’s existing water heater, which stays inactive as long as the water coming in is hot or hotter than the temperature setting on the indoor water heater. When it falls below this temperature, the home’s water heater can kick in to make up the difference. High-temperature solar water heaters can provide energy-efficient hot water and hot water heat for large commercial and industrial facilities