From ancient time people have also used solar energy for drying, cooking, heating baths and warming their homes. Without electricity, mankind learned to orient their buildings to capture the heat of the sun during the day.
The Greeks were the first to use solar architecture, over 2,000 years ago. They learned to build their houses to take maximum advantage of the solar energy. The sun’s rays entered their homes during the winter, but weren’t able to enter during the summer. There were entire cities built this way. The Romans, Egyptians, Chinese, and Native Americans also warmed their homes through passive solar energy designs. Anasazi Indians build cliff dwellings with southern exposures, providing passive solar heating and cooling.
The Romans first of all put glass in windows, which allowed the sun’s light to pass through but trapped its heat. They even built glass greenhouses so they could have fresh fruits and vegetables all winter.