"If the Earthship were a gasoline engine, Thermal Wrap and double or triple greenhouses would be fuel injection. I am ready to race any conventional heating system." - Michael Reynolds, Earthship Biotect.
We are looking for "no backup heating or cooling" designs. Early Earthship designs provided this to some extent with what we considered to be minor variable areas and some physical and emotional adjustment and commitment from the Earthship owners. As it turns out, this was asking too much of people, especially when there are still some remains of fossil fuels around for us to burn. The double and triple greenhouses and the thermal wrap together are proving to be an adequate evolution to achieve comfort for almost anyone. anywhere without fuel.
Thermal Wrap is less intense than fueled radiant heat, but there is more of it. More thermal mass = More stability. This is why we now use an uninterrupted thermal wrap equivalent to the floor area.
Q. What exactly do you mean by "uninterrupted" and how is this different from the Earthships in Volume III?
Surrounding the building with a volume of mass at least 4' tall x 4' wide and isolating it form the rest of the earth with insulation and having the north / south depth of the living spaces be no deeper than 20 feet to provide adequate relationship between the mass volume and the living space volume.
No interruptions all the way around the building except the south side which is solar gain. This results in the most stable buildings we have ever done. There are several tricks here - one being to equate the volume of thermal mass to the living space volume and another being to keep depth of space north/south to around 20 feet. The Comfort in Any Climate book goes into some of this discussion but more of it will come out in the second printing as we are fully impressed with the thermal stability achieved when these conditions are met.
The Thermal Wrap is outside the tire wall - between it and the earth berm. The tire wall is actually part of the thermal wrap. The living space is buffered to the south by growing spaces (greenhouses) that admit sun; and buffered on the north by an isolated and insulated thermal wrap. The living spaces are exposed only to the buffer spaces, not the outside or the earth - except for under the building which is taping the stable 58 degrees of the earth. It is a good idea to wrap the north side earth berm of your Earthship with 4" perimeter insulation. Go out about 6 feet and down to undisturbed earth. You will be glad you did.
"One thing I have noticed that I have not heard from anyone is that the temperature in every square inch of the space in the Earthship I am renting is "soft" - no drafts... it is even... throughout... very different from a "heated" space where there can still be a chill in the air even though it is 75 degrees. This is as good as I can explain it, but it is a phenomenon that is convincing me." - Earthship renter
We are simply adapting our needs to the already existing activities of the planet.
Why pipe water long distances from a centralized community water system, or from an expensive well that needs significant electrical power, depletes aquifers and lowers the water table, when water fall from the sky?
Why have a corporate or political "middle man" between us and our energy needs? our vessel (home) must be designed to sail with the forces that exist beyond human control and exploitation.
An understanding of mechanical systems for most humans is limited to what is within reach of their fingertips. It is understood that when you flip a switch on the wall, a light comes on. when you turn on the faucet, hot water comes out. When you pull the handle on the toilet, it flushes. Little though is given to where the electricity comes from or what kind of nuclear waste was produced to generate it. how many of us even know where the power plant is that supplies our power. Few people ever wonder which water table is depleted to bring them water and what chemicals have been added to it. Where does the sewage go after it is flushed and which rivers and lakes are polluted by it?
Humans need comfortable temperatures, light, electricity, hot water, food, sewage treatment, etc. These necessities are all available within the framework of a certain "rhythm" in the Earthship. The more we are able to align our priorities and needs with the prevailing rhythms of the planet, the easier and less expensive (both in terms of economics and ecology) they will be to obtain.
If our lifestyles can conform more to the patterns of the planet than to our socioeconomic system, we can reduce the stress on both ourselves and the planet. This is easier said than done due to the "reality" and the "gravity" of mortgage payments, utility bills and the generally high cost of eating and living. Most of us have no choice. We have to be places at certain times looking certain ways in order to make the money needed to make those payments. However, many people have built Earthships themselves and ended up with little to no mortgage payment. They also have little or no utility bills and their ability to grow food year-round inside the Earthship has greatly affected what they have to spend on packaged, processed foods.
The condition of our planet tells us we must now begin to take responsibility for what happens beyond the reach of our fingertips. We must begin to reconsider the source of these utilities, our access to them, and how we dispose of the waste produced. The mechanical systems of the Earthship confront these issues directly. We call this direct living. Source, access and destination are all contained within the Earthship, within the reach of our fingertips. There is no mystery involved in Earthship electricity. There is no unknown source of water. There is no magical black hole that sucks up all our sewage. Instead, we work in harmony with the earth to deal with these issues - taking what it has to give us directly and giving back what it wants to receive. With this harmony ringing in our minds we evolve the Earthship Systems.