A number of chapters are devoted to technologies that generate or save energy, such as photovoltaics (solar panels), solar hot water systems, small-scale wind systems, hydro power, and ground source heat pumps (GSHP). These chapters should prove very useful to owners of existing homes in making them more eco-friendly, as also to designers and ecohouse builders. The other part of the energy equation is also covered well. There is a good discussion of the energy that has gone into the various materials we use in constructing our dwellings, as also of the emissions for which they are responsible. The terms embodied energy and embodied emissions are used. The term embodied energy stands for all energy used to create an object, from "extraction of raw materials, transportation to processing plants, energy used in factories, transportation to site, and energy used on site to install the product," while the term embodied emissions stands for all emissions, mainly of CO2, but also of toxins, released during its creation.

When one considers how many distinct products go into a house, the mere thought of trying to determine not only the embodied energy and emissions of each product, but indeed of the entire house, may well result in an overheated brain and complete loss of motivation. It seems overwhelming. The ideal would be to have a comprehensive and straightforward list of products and their embodied energy and emissions. Figures of these things are not yet widely available, but it is argued, quite sensibly, that what we really need is to understand the factors affecting embodied energy and emissions so that we can ask the right questions when selecting materials. Ecohouse devotes a fair chunk of space to this topic, including a section on the embodied energy of different building materials from plastics, to metals, to timber. There is also a case study and a good recommended reading list on material selection and life-cycle analysis.

In "Building-in soul," material selection is revisited in a different context. Building one's own house, though expensive, is not nearly so expensive, "perhaps not one-fifth, so expensive as having something built for you." And it is further pointed out that "most importantly, you invest your soul in what you build, which is why self-built homes are so soul-rich to live in." What buildings are made of, it is emphasized, contributes greatly to their character.

Wood, earth, brick, concrete, steel, glass or plastic buildings are totally different from each other to see, to live in, to build and in the forms their construction logically and characterfully demands. . . . So, very important in terms of their pollution and environmental costs, are their manufacturing biographies and how they end their life — do they return to nature or become refuse?

Though this chapter goes well beyond the selection of materials, discussing such things as the character and identity of a building, especially one self-built, as well as its connections to a wider community, economy and ecology, it also does a good job — better than the earlier argument against the building-as-a-machine analogy — of getting to the root of the difference between the common mass-produced house and the ecohouse. Materials, we are told, "connect us to the world from whence they came: living and life-cycle bound by nature, or lifeless, dead industrial processes." And the following quote both provides a general rule for material selection and a summary of how to create a vibrant, connected, almost living house:

We use thousands of materials in modern building, but a general rule is that the nearer something is to life, the more compatible it is: the healthier to live with, the more recyclable back to earth, thence to living matter again. It also needs more care for longevity — but this care, like the care given to its making, is imprinted into its substance and emanates from it, to nourish those who live next to it. Mass-produced products can never do this; the imprint of care is, by definition, absent.

There is a bit too much talk of soul for me here, giving it somewhat of a New Age tone, but that is mainly a matter of word choice. I would have just stuck to the language of psychological and emotional connections, as that is what it really comes down to.