Green to the Extreme: Earthships Green to the Extreme: Earthships
There is a belief among green enthusiasts that everything can be resused or recycled. There are buildings in the country today that reflect this opinion, and there are advocates, such as "biotecht of Earthships" Michael Reynolds in Taos, New Mexico, who do something about it. Mr. Reynolds believes it is the narcissism of architects that prevent many buildings from being earth friendly. There is a whole culture built around these ideas.
What is an Earthship?
An Earthship is defined as an earth-sheltered building made of tires that are rammed with earth. Generally, they are built in a "U" pattern. The tires are filled with earth and jammed full using a sledge hammer. Windows are placed on the sunny side -- facing south in the northern hemisphere and facing north in the southern. The roof is heavily insulated. Walls are built with recycled cans separated by concrete. They are then thickly plastered to provide insulation. These walls are called a "tin can wall."
Earthships were originally designed to exist in harmony with nature. To be self sustaining, they must produce their own utilities -- water, electricity and heat. This is done in a variety of ways.
What are the Advantages?
- An earth-bermed home with sun-facing windows produces natural heat.
- Earthships collect rainwater from the roof, which reduces runoff impact and lowers water and sewer bills.
- Because they use wind power and photovoltaic cells to produce electricity, they are earth friendly.
- Their U-shaped design makes good structural sense.
- They are built with tires, which are free. They also remove these tires from the recycling system.
- Runoff, greywater and blackwater are routed to plant beds.
What About Disadvantages?
- They may be hard to keep water tight.
- There may be significant heat loss if not designed correctly.
- Because they are so unique, they may be hard to sell.
- Building an Earthship is very labor intensive.
- Because of intimate earth contact, health hazards such as Radon may be a problem.
- Tires are not structurally stiff, and may require reinforcement.
How Do Earthships Produce Water?
The concept is simple -- water or snow runoff from the roof is collected in a cistern system. Cisterns are designed so that a pump will run the water through a filtering system, making it suitable for drinking. Greywater is fed into a botanical rubber cell, where it is filtered through a combination of gravel and plant roots. This recycled water is then used to flush toilets. Blackwater is not used in the earthship, but is instead channeled to a solar enhanced septic tank. The sun's heat is used to complete the anaerobic process. The water is then channeled to outdoor planter cells, much like the botanical cell used in dealing with greywater.
What About Electricity?
Electricity in an Earthship is produced by solar panels and wind power.The electricity is stored in batteries, servicing the home. Additional electricity is gained through gasoline powered generators or off the grid. No electricity is used for heating or cooling.
How Is Climate Controlled?
Earthships take advantage of the natural tendencies of the earth itself. They use thermal mass and solar heating and cooling. Their design is such that they are earth-sheltered. The advantage is twofold: they take advantage of the thermal mass of the tires, and utilize the earth's inherent stable temperatures. The thermal mass of the steel-belted tires and earth soaks up heat during the day and releases this heat at night, keeping the interior warm and comfortable.
The scope of this article cannot touch on all the information about earthships. A great deal of information is currently available on the internet, including a step by step guide to building an earthship. Links, resources and images are readily available. If you have ever considered building an earthship, be sure to look over all this available information. Building an earthship is not only fun, but is a very good way to build a self-sustaining home. The savings in utilities alone make this project well worthwhile.