You are probably familiar with the type of solar system that generates power, Solar Photovoltaic. But there is a lesser known use for solar energy from the sun that helps homeowners conserve energy. And, in most cases, it costs less than installing a solar PV system. It is called Solar thermal. Solar thermal heats water with the power of the sun and stores that hot water to be used in your home. This replaces energy consumed, in the form of natural gas or electricity, to heat water and keep it hot. And when you consider that this function comprises 25% of your home's energy use, you are looking at a significant savings. Watch this video to see how a two types of Solar thermal water heaters are in use at Southface Energy Institute in Atlanta, Georgia. Solar thermal is part of the Top 11 things I think you need to see at Southface. There's a video about that here.
For a short overview of the three primary types of Solar technologies, watch Solar 101.