Our Small Cabin which is located in the same general area (20 mile radius) as a handful of the most sustainable “sub-divisions” on the planet. I use quotes around the term subdivision because it is about a far from your typical development as you can get. The most famous, or infamous is “The Greater World Community” This community consists of a bunch of Earthships, for those that do not know what an Earthship is you can check out this link Earthship definition.
The basic principle of the Earthship is that it is self-sustained and built from a lot of reclaimed materials (tires, cans, and bottles). By being passively solar heated they require no power source to heat or cool. Earth sheltering is one of the main reasons why they work so well. Earth sheltered homes are not subject to the temperature swings of the air…they are buried mostly into ground, which for any given area will have a constant temperature.
One of the original motivations of early man’s movement into caves was probably the ability of the earth to naturally even out variations in temperature. At depths of about 20 feet (6m) temperature is naturally “annualised” at a stable year-round temperature.
With the development of modern passive solar building, during the 1970s and 1980s a number of techniques were developed in the US that enabled thermally and moisture-protected soil to be used as an effective seasonal storage medium for space heating, with direct conduction as the heat return method.
Two basic techniques can be employed:
- In the Passive Annual Heat Storage (PAHS) and similar direct solar gain systems, solar heat is directly captured by the structure’s spaces (through windows and other surfaces) in summer and then passively transferred (by conduction) through its floors, walls (and, sometimes, roof) into adjoining thermally buffered soil. It is then passively returned (by conduction and radiation) as those spaces cool in winter. These techniques were advocated in Daniel Geery’s 1982 book Solar Greenhouses: Underground and John Hait’s 1983 Passive Annual Heat Storage.
- The Annualized Geothermal Storage (AGS) concept involves the capture of heat by isolated solar gain devices (rather than the building structure). From here it is deposited in the earth (or other storage masses or mediums) adjoining the building using active or passive technology. The depth at which the heat is deposited, is calculated (according to soil type) to provide a controlled 6-month heat-return time-lag to the building through conduction as the building cools. This alternative was posed by Don Stephens.
These concepts are compared in greater detail at: www.greenershelter.org.
So now we have a few ideas swimming about in our heads…Small simple structures that are economical to live in by their mere size , or larger structures that heat and cool themselves. I feel that a lot of the small house movement is based on having a smaller footprints in the world, be it a “carbon footprint”, or the real foundation of the structure we call home. Most Earthship owners love the idea of a completely sustainable lifestyle for heating, water and power (earthships have PV panels). A lot of Small house lovers can also do this and have the added benefit of being mobile (The Tumbleweed house on a trailer is a nice example). Both small house builders and Earthship builders often do a lot of the work themselves, and here lies the BIG difference. Most Earthships use literally TONS and TONS of material, and it is very labor intensive to pound all that dirt into those tires, and hand build all those cement and bottle walls. Small houses are just small, and for that pretty easy to build.
Tori and I love the idea of a zero utility structure, we like the water management issues of the Earthships, the Growing beds etc. Its just the idea of pounding tires for 5 years that does not appeal to us. So we have the Idea of a Hybrid…Earthship. This design uses ICF’s (Insulated Concrete Forms) or more traditional concrete walls. The use of fly ash, and modified cement recipes can remove a lot of the undesirable aspects of regular concrete and its high embodied energy. We feel that our zero carbon emissions for the life of the home will off set the carbon emissions of concrete use. With an Earth Sheltered home you get all the benefits of an Earthship with out having to pound hundreds and hundreds of tires.
The use of southern exposure windows and an open floor plan will eliminate the cave or basement feel, and provide all the passive solar heating. We will still use the off grid, water harvest / reuse aspects of an Earthship…after all growing fresh tomatoes or Bananas in the living room is good thing. For those long sunless spells a wood stove will help keep us warm if needed.
For those that want a little more info, Mike Reynolds, the architect creator of the Earthship idea has a new documentary out…its called Garbage Warrior and I recently watched it on the Sundance Chanel. It covers a lot of the headaches of dealing with governmental agencies and all the hurdles they put in place for free thinking and innovation design….Thanks Mike for paving the road for all of us that follow.