What is an Earthship?
An Earthship is a low-impact sustainable building that is made out of ‘rubbish’ – mainly car tyres, cans and bottles – which reduces the use of concrete, damaging to the environment, by nearly 80%. The building design incorporates it’s own energy production, rain water harvesting and filtration, food production, sewage treatment and thermal mass/passive-solar heating and cooling.
- Earthships enable us to live more in harmony with our environment
- Earthships Reduce, Re-use and Recycle
- Earthships can help mitigate climate change
- Earthships can make us more resilient to climate change
- Earthships can give you freedom and autonomy from bills and inefficient centralised systems
- Reliance on polluting and non-renewable energy sources
- Rising energy costs
- Food security and rising costs
- Limited freshwater reserves
- Growing piles of rubbish in limited landfills and increasing problems with the disposal of hazardous waste
- The urgent need to reduce CO2 emissions to mitigate climate change
- Sewage systems that use the precious and limited resource of of clean water
- Increase of floods and droughts
The list goes on…
- The amount of CO2 emissions that construction can influence is significant, accounting for almost 47% of total CO2 emissions of the UK. (Report from the Department for Business and innovation Skills, 2010)
- There are about 3 billion tyres dumped every year – 40 million in England (about 440.000 tonnes/year). The cost of getting rid of tyres in England is currently £56 per tonne (it was £7 in 2000) and will be £80 in 2014 in tax alone.
Earthships provide a solution to many of these issues through their design and integrated systems:
Building with recycled and natural materials
Earthships use old car tyres, rammed with earth and stacked to form the main load-bearing walls. Not only does this productively utilise an otherwise problematic waste material, these walls are very thick and solid, with high thermal mass, which contributes to the maintenance of a comfortable interior temperature of the building and also means there is no need for traditional foundations. These walls can be encased either in concrete or cob with a natural clay & lime plaster. The interior and non load-bearing walls are similarly made from bottle-bricks or aluminium cans. These look great and re-use these waste materials. These techniques can reduce the amount of concrete used in construction by nearly 80%.
EARTHSHIPS HAVE 6 FUNDAMENTAL PRINCIPLES:
Heating and cooling
The building design uses a combination of thermal mass, passive solar design and insulation to regulate internal temperature fluctuations. The buildings are designed with a double or triple glazing running the length of once side, oriented to receive the sun’s rays and maximising the rays recieved in winter. During the day, the sun heats the thermal mass of the walls and floor, which absorbs and holds the heat. At night, this heat is radiated back into the internal space, keeping it warm. To cool the building, the sun entering the building can be blocked, and the coolness stored by the earth is transmitted into the building. The design can also make use of various ventilation shafts that can be used to move air as needed through the building. The result is a building that maintains a comfortable interior temperature throughout the year and minimises or eliminates the need for additional heating.
Electricity, generated on-site by solar photovoltaic panels and a wind turbine, is stored in a panel of batteries and connected to an invertor, or Power Organising Module, which supplies electricity to the building. The POM can also accept electricity from a gasoline generator or the city energy grid. (In the case of wind turbines, it is usually more efficient to invest in larger turbine(s) as a community). During the day, sunpipes reflect the daylight down into the interior spaces, reducing the need for lighting. A solar thermal hot water system heats water with the sun’s energy, and a gas-on-demand boiler or biomass heater/stove/boiler can also be installed to heat water when the sun is not enough and to top up the heat inside the building. Using a combination of these technologies as appropriate, it is possible to live off-grid with zero or very low energy bills, or to feed energy back into the grid if you’re connected to it.
Food is grown in indoor planters and watered using filtered nutrient-rich ‘grey water’. The interior space is like a greenhouse, so extends the growing season and enables a diversity of foods not otherwise possible (eg bananas in France!) Indoor growing not only limits the amount of plant pests to contend with, the plants enhance the living space, and there’s nothing better than to be able to pick your own within meters of your kitchen! Aquaponic systems could also be incorporated, and food can also be grown organically in the area around the building.
Rain water and snow melt is collected off the roof, filtered for silt and stored in large cisterns which are usually buried in the earth to protect them from the sun. From here the water is further filtered and cleaned for human consumption and can be used from the taps as usual. Once this water has been used (eg for showering, washing up etc), this ‘grey water’ is filtered and passed into the indoor planters for use by the plants. The plants also help to filter this water, which is then used to flush the toilet. After the toilet, this ‘black water’ is contained and treated and this nutrient-rich water can then safely be used on plants outdoors. Thus the water is re-used 4 times and reduces the amount of water consumed!
All sewage is contained and treated on-site . Once the toilet has been flushed with ‘grey water’ (see above), the ‘black water’ from the toilet goes to an exterior septic tank. From there it goes to a leach field, or a reed-bed treatment system, which naturally filters the water using layers of gravel, sand and reeds. Alternately , the water can be directed from the septic tank to a rubber-lined contained botanical cell. The water can then safely flow to the surrounding land without contaminating the water table or aquifers.