Earth-sheltered homes first enjoyed popularity in the 1970s, as an oil embargo and resulting energy crisis left U.S. citizens scrambling for more energy-efficient building methods. An earth-sheltered home can range from a home constructed in a cave to one with earth piled in berms against the exterior walls. Those who have built earth sheltered homes claims they reduce heating and cooling costs by half, with very little increased construction expense. Most homes also blend in seamlessly with the landscape, making for an attractive natural setting.