Cliff Dwellings - Natural Solar Homes

Grand Gulch Cliff Dwelling

Cliff dwellings as found in Southern Utah are almost always in south facing alcoves with overhangs because this situation provides the optimal situation of providing a cooler environment in the summer and a warmer environment in the winter as well as protection from rain. In the summer the zenith angle is low (sun is nearly overhead) during most of the day ensuring that an overhanging roof will provide a cool shady environment. During the winter the zenith angle is greater (sun is lower in the sky) and the sun shines underneath the overhang to provide warmth if the home alcove is facing south.

Figure 1. Zenith (angle from sun to vertical) and azimuth (compass direction) for mid latitude location.

The two pictures of ruins were taken in late fall near the time of the winter solstice. Notice how the sun shines directly on the ruins because the low angle of the sun allows the rays to reach under the overhang. In the heat of the summer the same locations are shady and cool.

Banister Ruin, Grand Gulch, UtahI

Banister Ruin, Grand Gulch, Utah