For the Northern Hemisphere

Solar architecture has a long history of use. Some of the earliest buildings in the Southwest that took advantage of the sun were the Indian cliff dwellings, which in many cases faced south. This allowed the low winter sun to enter and heat the mud and stone walls of the apartments inside. During the summer the cave roof shaded the dwelling from the direct rays of the sun.

The same time-honored techniques are used today to design homes that are comfortable in both winter and summer with little or no need for additional energy. Passive solar homes use the sun along with heat transfer mechanisms of convection, conduction, and radiation to provide year-round comfort. Solar homes that depend on fans and pumps for heating and cooling are called active systems. If a small amount of energy is used to run a fan and distribute heat (or cool) throughout an otherwise passively heated house, the system is referred to as a hybrid.

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