A solar water heater uses solar energy to heat water and consists of solar collector panels and an insulated storage tank. The panels heat water that circulates between the storage tank and collectors. Heated water is then available for use. There are two main types: flat plate collectors and evacuated tube collectors. Evacuated tube collectors are more efficient, working even in cloudy or rainy conditions using vacuum tubes and heat pipes. A solar water heater can provide over 70% of hot water needs and saves money on utility bills while reducing carbon emissions compared to electric or gas water heaters.