Underground homes and earth-sheltered homes are among the most popular types of alternative homes. Almost everyone knows the earth will moderate the inside temperature and reduce energy costs. That’s why potato storage cellars are common. These structures will “assure the grower that potatoes will be held at the proper temperature from harvest time to shipping time, anywhere from March to May.” Of course, the same principle can be used to build energy efficient homes, storm shelters and rootcellars.