The term Earthship describes a particular type of house that, in the terms of Michael Reynolds, “interfaces” with the earth rather than combats it as is the case with most traditionally built structures. Although there is a specific organization founded by Reynolds, known as Earthship Biotecture, that constructs these houses the Earthship is meant to be a house that can be built by a layperson without having to receive the permission of the organization. Earthships are presented as highly sustainable structures, carbon neutral and at times, carbon negative.
Earthships are built largely out of recycled and readily found local materials. The exterior load bearing walls are made from car tires rammed with earth, interior walls are made from recycled bottles and cans. Even detail features can made from recycled materials.
Earthships can be easily distilled into their most fundamental components and described by the concept of “interfacing” with the Earth.
Heating and Cooling is done using no electricity. The outer few feet of the earth heats up and cools off in response to surface weather. However, deeper in the earth, about four feet and beyond, the temperature is more constant (around 58 degrees). Here, the earth can be used to both cool and stabilize temperature if the home is appropriately designed.
Each Earthship has a U-shaped structure made of rammed earth;i.e. Thermal Mass. This thermal mass provides a stable 58 degree temperature. The south facing glass of the green house allows the proper amount of sunshine in to “charge” the thermal mass. The walls retain the heat, then at night when there is no sun radiates the heat back into the room. The process is repeated everyday.
Water is another essential system that typically relies on large scale infrastructure. Water falls freely from the sky. The Earthship employs a rainwater collection technique that catches runoff from the roof and stored in cisterns. The water enters the home through a filter system and used traditionally. The water that runs down your drains, flows through the greenhouse via botanical cells, which filter the water again so it can then be used to fill the toilet.
Electricity is “harvested” from the sun and the wind. Solar panels convert the sun’s energy into DC current electricity and is stored in “golf-cart” type batteries. An Earthship Power Organizing Module draws the electricity from the batteries, inverts some of it for AC electricity and supplies it to the home. The POM can accept electricity from a generator, wind turbine, or micro-hydro source.
Earthships contain, use and reuse all household sewage in indoor and outdoor treatment cells. This results in food production and landscaping with no pollution of aquifers. Toilets flush with treated gray water that does not smell.