An earth-sheltered house is a dwelling built into a hillside or otherwise constructed to be partly or fully subterranean. The primary benefit of these structures is natural insulation; houses sheltered in this way are protected from fluctuating external air temperatures. There are some drawbacks to an earth-sheltered house, particularly involving moisture; they must be carefully designed and constructed. While people have lived in earth-sheltered houses throughout history, they were the subject of renewed interest starting in the late 20th century.
Earth-sheltered houses date back thousands of years. Surviving structures from past eras can be found in Scotland, France and Iceland, among other places. These structures used mounds of earth, called berms, to protect the house from exposure to the elements. Other structures took advantage of caves or other natural formations, such as the Gila Cliff Dwellings of New Mexico. An ancient underground structure in Tunisia gained worldwide fame in 1977 by providing the set for Luke Skywalker’s desert home in the first “Star Wars” movie.
During the 1970s, alternative communities rediscovered the advantages of the earth-sheltered house. Counterculture publications such as “The Whole Earth Catalog” offered plans and materials, and many were constructed across America and the world. They sometimes became part of communes or intentional communities, such as Whitehawk near Denton, Texas, and the Earthship communities of New Mexico. The buildings often include solar panels and other measures to increase independence from public utilities.
The relatively low energy requirements of earth-sheltered houses make them ideal for these kinds of alternative communities. Natural insulation contributes to this low energy usage. Other benefits include increased soundproofing and privacy from neighboring houses. Some owners also find them aesthetically pleasing, because they blend in with the surrounding terrain and ecosystem rather than disrupting it.
Disadvantages include moisture seepage and condensation from the earth surrounding the house. Air circulation can also be a problem. These houses must be constructed with careful attention to the local climate, soil and drainage. Most require additional insulation between the earth and the house to regulate temperatures during summer and winter months. Otherwise, the house is at the mercy of the weather. These issues must be resolved before construction starts.