In the early part of the 20th century Arizonans discovered that hot water for household purposes could be supplied by heating water with sunlight. This led to one of the first commercial solar energy products, the Day and Night Solar Water Heater.
In the early part of the 20th century Arizonans discovered that hot water for household purposes could be supplied by heating water with sunlight. This led to one of the first commercial solar energy products, the Day and Night Solar Water Heater.