Earthship as an alternative?

About Earthship

Earthships are buildings of a specific construction style that are heated only by passive solar heat gains and the storage of this heat using thermal mass or cooled through natural air circulation. They are also characterized by extensive use of natural and recycled building materials as well as complete self-sufficiency in terms of heating, electrical energy, water, and wastewater.

A special feature is the use of civilization waste as building material. For example, the closed north, east, and west walls are almost always constructed from used car tires. These are stacked like bricks in a composite and filled with compacted earth. The resulting wall serves as a load-bearing element and additionally acts as a thermal storage due to its large mass, which usually weighs several tons. The south-facing facade exposed to the sun is almost completely glazed. The solar heat gains generated here are stored in the massive components over days and weeks, so that no conventional heating is needed.

For self-sufficient water supply, rainwater is collected on the roof area and stored in cisterns. An elaborate system allows every drop of water to be used up to four times. This makes a self-sufficient water supply possible even in arid areas with very low annual rainfall and no additional external water supply. The rainwater is filtered and used as drinking or flushing water. Afterwards, it irrigates a planter inside the house and is thereby purified. The treated water is then used again for toilet flushing and finally routed through a septic tank into a planter next to the house, where the last impurities are filtered out by plants.

The Earthship principle was developed in the 1970s by the American architect Michael Reynolds. About 30 years later, the concept spread due to increasing awareness of climate protection and sustainable building methods – also outside the United States. The buildings are today designed and marketed by Reynolds’ company Earthship Biotecture in Taos, New Mexico. In addition to planning and constructing the buildings, plans and books for self-construction are also offered.
By 2006, about 2000 Earthships had been built, all except two in the United States. At least 1000 other buildings are based on the same principles but were created without the involvement of Michael Reynolds or Earthship Biotecture. Since then, projects have been added in Canada, South America, the Caribbean, India, and Africa. Besides residential buildings, accommodations for victims of natural disasters in Haiti and India as well as a Waldorf school in Sierra Leone were built. The buildings take into account the different climatic conditions of the locations.

In Europe, buildings have been realized in the Netherlands, Belgium, France, Spain, Portugal, Great Britain, Sweden, Iceland, Estonia, and the Czech Republic. The first project in the German-speaking region is an Earthship planned in the Tempelhof community (Baden-Württemberg). Construction of the prototype began at the end of September 2015 and is scientifically accompanied by the University of Stuttgart, especially regarding building physics properties. To achieve a planning approval, unlike a classic Earthship, full use of rain and wastewater was omitted. However, all technical systems of a typical Earthship are installed despite the limitations on water use to enable a complete functional analysis. Furthermore, unlike previous Earthships, the building received a complete capillary-breaking floor insulation made of foam glass gravel.

The transfer of the Earthship principle to the moist cold climate of Northern Europe initially led to technical problems, especially with condensation. Construction and operation of the Earthship in Brighton (Great Britain) were therefore scientifically accompanied and documented by the Center for Sustainable Construction at the University of Brighton. A bachelor thesis at the Danish Via University College deals with the question of the applicability of the construction principle in the Nordic climate of Denmark.

The roof surfaces of Earthships are designed so that all precipitation (water, snow, dew, and condensation) flows into a mostly underground cistern. The water is first routed through a gravel filter to prevent coarse contamination from entering the cistern. The cisterns are usually arranged so that they lie in a north-facing sheltered terrain – roughly at the level of the indoor rooms. Due to this elevated position, the water can flow downhill into the interior without an additional pump, where it is treated in the so-called “Water Organization Module” (WOM).

The WOM consists of a direct current powered pump and a series of filters. Only the water actually used as drinking water passes through all filter stages. Therefore, every sink is equipped with an additional tap for drinking water. Using the pump, water is pumped into a pressure vessel that supplies the house network with standard water pressure. The treated water is used for all household applications – except for the toilet. There, only once-used water from sinks, showers, or washing machines is used, which has previously been filtered in “graywater” planters.

*Source: Earthship Deutschland.de
**Images Water Management, Earthship located in Taos N.M, Earthship inside greenhouse + Rights holder: Amzi Smith (This file is licensed under the Creative Commons License “Attribution – ShareAlike 3.0 Unported”).

Rhenish greetings

Cross-section through a greywater plant bed (system)

Greywater refers to water that is already contaminated but not polluted with fecal matter and can no longer be used as drinking water. This contamination usually consists of non-toxic substances such as soap, skin particles, or hair. In the Earthship, it is roughly filtered from fat and solids and directed into plant beds up to 150 cm deep. These beds are located inside the building directly below the glazed south facade. The plants there filter the water together with the microorganisms in the soil and use any nutrients from, for example, detergents—such as phosphates and nitrogen—for their growth. They also enrich the indoor air with oxygen and water vapor and can serve food production if vegetables or dwarf fruit trees are planted there.

When the greywater reaches the end of the bed, it collects in a reservoir and, after passing through another filter, is used for flushing the toilets.

After initial experiments with compost toilets, all newer Earthships now use this system with water-flushed standard toilets. The resulting water contaminated with fecal matter is called blackwater. This is channeled outside, where it is decomposed by anaerobic bacteria in an insulated and solar-heated multi-chamber septic tank. From there, it is led to a constructed wetland, where it can be used, for example, to irrigate ornamental plants or fruit trees.

Earthships generate all their electrical energy through photovoltaics and in some cases through small wind turbines. The electricity is stored in batteries, further distributed in the so-called “Power Organizing Module” (POM), and converted to alternating current there—if necessary. Ideally, the most important consumers such as pumps, refrigerators, and at least some lights use direct current. This way, the essential functions of the house remain operational even in the event of an inverter failure. Alternating current is used for all other applications such as computers, internet connection, or the washing machine. To achieve complete autonomy even with relatively little battery capacity, electricity is not used for heating or air conditioning. Instead, service water is heated by solar energy and only in case of extended cloudy periods by a wood stove or a gas boiler.

Most Earthships do not use electrical ventilation but simply vent warm air through skylights. These are usually simple sealed flaps that are operated by an internal cord and can be kept open by a counterweight. The rising warm air creates a chimney effect that draws cooler air through windows or earth tubes. This creates a constant light breeze in summer and carries off excess heat. In winter, air slightly preheated by the ground flows into the house, or the intake openings are closed during the winter months.

Depending on the climatic conditions and ventilation behavior of the occupants, this form of air exchange can lead to moisture problems, which is further favored by the large number of plants inside. Some Earthships have therefore been retrofitted with mechanical ventilation with heat recovery.


How much does an Earthship cost?*

The total cost of an Earthship mainly depends on how much work you can (or want to) invest yourself and on which materials you use. Since there are still no Earthships in Germany, we can only refer to experience from abroad. We think that an Earthship costs roughly the same per m² as a regular passive solar house. Although a lot of material is used in Earthships that our society usually throws away, certain things still have to be purchased or at least sourced and transported. Inevitable costs arise mainly from the systems (photovoltaics, wind energy, water pumps, water treatment, water tank, etc.). Depending on requirements, the systems must be professionally installed. For example, if many electrical devices are to be used simultaneously, significant funds must be planned for the systems to ensure energy supply.

In the USA, a Simple Survival Earthship with about 50 m² of living space can be built from around 50,000 US dollars with high self-labor. A Global Model Earthship with about 120 m² of living space costs turnkey approximately 300,000 US dollars with very little self-labor. These numbers are to be taken as rough guidelines.


How are the costs distributed?

Materials (40%)

[*]Many of the materials, such as car tires, glass bottles, and cans, can be upcycled. Nevertheless, costs may arise when sourcing them.
[*]Wood, cement, sand, gravel, rebar, insulation, and many other building materials usually have to be purchased.
[*]Windows and doors entail high costs if bought new.

Construction costs (40%)

On the one hand, costs arise for the actual work done on site. However, preparation and planning must not be neglected. Although it is our passion to build Earthships, we cannot (yet) live on air and love alone. To support people as well as possible, costs arise for:

[*]Project support
[*]Architectural planning
[*]Expertise of specialized craftsmen on site
[*]Costs for further training
[*]Travel expenses
[*]Technical infrastructure
[*]Tools
[*]Provision of food for helpers (depending on project size up to 40 people for 6 weeks)

Systems (20%)

[*]Photovoltaics
[*]Wind power
[*]Electronics and batteries
[*]Water management
[*]Botanical cells

What are the ongoing costs?

In an Earthship, there are no costs for water, heating, and electricity. Excess electricity can be sold via grid connection.

Costs arise for gas in the kitchen and for maintenance of the systems and batteries.

*Source: Earthship Deutschland.de
Earthship Zwolle image + rights holder: Erik Wannee (This file is provided under the Creative Commons License “CC0 1.0 Universal Public Domain Dedication”).


Rhenish greetings

The idea sounds exciting - but I would be skeptical especially about the recycling. Car tires also contain a lot of chemicals. Batteries certainly don't have the best footprint either. Also, the pictures don't look like $50K USD - of course, it can be deceiving and there is really someone with a lot of skill behind the DIY work. By the way, in retrospect, I definitely would have had the Styrodur boards installed (if he still remembers) and would not have insisted on new ones.

Interesting project. If we ever want to build a house again and the children have already moved out, I would revisit this. At that future point in time, development will have progressed, new experiences with such a project will have been gathered, and some issues may have been resolved, so the concept might be further optimized. I would be interested, for example, in the development/research in Denmark / Sweden regarding cooler climates, since Norway is somewhat my dream country. I am not really an "environmentalist." However, the possibility of a largely self-sufficient lifestyle fascinates me. As for the price – well, our current Kfw70 house also cost that much – but with 170 sqm. The only thing that bothers me a bit about the pictures is that the entire complex seems to be one large room – separation mainly only by cabinets and similar – or did I miss something here.

Such a construction method is currently never feasible in Germany. All building materials require approval by the building authorities, connection to drinking water and sewerage systems is usually mandatory as well – there are certainly not 100 other reasons. I might want to live somewhere in the middle of nowhere like this, but like this... no.

Such a construction method is currently never feasible in Germany. All building materials require official approval, connection to drinking water and sewage systems is generally mandatory – there are certainly about 100 other reasons as well.

As the first project in the German-speaking region, an Earthship is planned in the Tempelhof community (Baden Württemberg). Construction of the prototype began at the end of September 2015 and is being scientifically monitored by the University of Stuttgart, particularly regarding the building physical properties. To achieve a planning approval, unlike a classic Earthship, the full use of rain and wastewater was omitted. However, all technical systems of a typical Earthship are installed despite the limitations in water use to enable a complete functional analysis. In addition, unlike previous Earthships, the building was given a complete capillary-breaking floor insulation made of foam glass gravel.

Well – German bureaucracy and regulatory zeal could indeed pose a problem here. Although they often provide citizens with (legal) security first. On the other hand, the pilot project was approved. Once it is established and further data/facts have been collected, a rethinking in the administrations might occur in the future. It is usually like this – when a reference exists, eventually a "courageous" official steps forward and sets a precedent (approval). Once an approval exists, the following approval processes become easier as a precedent case already exists.

btw. in my thought experiment, about 20-30 years still lie ahead of us