They may look a bit dated at first, or at least more whimsical than required for functional living. Still, these earth houses have more to offer than custom curves and a unique aesthetic – including a set of design philosophies, strategies and tactics that are far from just superficial nods to sustainable trends. The designs take everything into account from fire and earthquake protection to integral  insulation-efficient arches and buffer rooms for energy-free temperature control.

While not every Erdhaus is actually built under the existing ground on a site, they are all tied to their earthen surroundings by sloping sheaths of greenery. Grass-covered walls curve up and continue as green roofs along the tops of each structure. The resulting contiguous thermal mass of this all-in-one exterior wall-and-roof system helps to conserve heating and cooling power.

Some of these are built as continuous strip communities, a kind of eco-suburb that looks from a distance like a simple set of rolling hills. This results in reduced material and construction costs as well as additional power savings due to shared party walls.

From an energy generation standpoint, all of the standard sustainable solutions are also available: geothermal, water, solar and wind. Moreover, there is an underlying visual theory that informs these shapes as much as these functional requirements – they are intended to mimic the naturally abstract and seemingly random curves of their natural surroundings. While not everyone wants to live in something so exotic-looking it is at least noteworthy that their design philosophy carries all the way from construction methods to the aesthetic appearance of the final product.