Solar electric and solar thermal: Using the sun to save money

(This post was written by MD SUN Communications Fellow Garance Perret)

When people talk about ‘going solar’, there are two technologies they generally mean: solar electric and solar water heating. Although they both use the sun’s energy, solar electric systems and solar water heating systems use that energy in different ways.

Solar electric systems use sunlight to generate energy. Light particles hit electrons in the panel, creating an electric current. This current then powers your home and appliances. Solar electric systems vary greatly in size. They can be as small as a handful of panels on a remote hunting cabin, a few dozen panels on your home, or thousands of panels arrayed in the desert.

Solar water heating systems use heat from the sun to raise the temperature of the water you use in your home. This is done either by heating the water directly, or by heating a transfer fluid.

The collectors used in solar thermal systems do not have the complex electronics that solar electric panels have. In solar thermal systems, water passes through the collectors’ tubes where it is heated by the sun’s energy. The water then goes through a heat exchanger for storage and later use. The system is accompanied by a water tank modeled on a standard hot water heater.

As with solar electric panels, solar hot water systems do need occasional maintenance over their lifespan. Your water pump may need replacement once or twice over the roughly 30-year life of the system. You should also have your transfer fluid checked every three to five years.

You can learn more about solar hot water systems here.