Jesse Ausubel's review (Ausubel, 1982) of our recent joint analysis (Lovins et al., 1982) stimulates us to suggest, in the same friendly spirit, a few respects in which he missed the mark.
In considering how little energy could be used, and how little fossil fuel burned, if people used energy in a way that saved money, we do not feel we were being 'extremely optimistic[', but rather soberly realistic. Perhaps Ausubel means by 'optimistic' something like James Branch Cabell's remark that "The optimist proclaims we live in the best of all possible worlds; the pessimist fears this is true." But the word implies that he thinks we are extrapolating unique, best-case results as if they could be achieved everywhere.
Someone not acquainted with the extraordinarily rapid recent progress in technologies for wringing more work from each unit of energy might easily jump to this conclusion. But the empirical cost and performance data which we document in considerable (some would say tedious) detail tell quite the opposite story. Verifying the references will confirm that we have consistently assumed less-than-best-case technologies, slowly and unevenly applied, with robust rather than arguable cost advantages. This is illustrated by the Saskatchewan Conservation House, a best case which Ausubel apparently assumes we believe will be universally replicated. Since its completion in late 1977, that model house has achieved, as we state, 'the best heat loss value' of any house documented up to late 1981: its net space-heating requirement is only 2.8% that of an average 1973 West German dwelling. But we do not assume that German dwellings will ultimately reach this standard (even though they probably could). Rather, we assume the net space-heating requirement for new houses in Germany will eventually fall to nearly twice that of the Saskatchewan Conservation House, and that retrofits will eventually improve old German houses so that they need only nine times as much heat as the Saskatchewan model. (We conservatively assume that apartments need as much heat per square meter as single-family dwellings; in fact they need substantially less because they have a smaller surface-to-volume ratio.) Whether Ausubel believes them or not, the superinsulation costs we cite (which have since fallen in real terms) have been empirically confirmed not just in one house but in thousands of houses, built in several countries, using at least a dozen basic designs. Indeed, many of those houses, by using new and highly cost-effective technologies, have reduced heating requirements to essentially zero, even in severe climates.
Ausubel's $360+-per-window price quotation for triple-glazing his existing windows shows two things. First, retrofits, though often worthwhile, do generally cost more than building things right the first time: our housing examples show the typical ratio is about five to twenty. (Ausubel decreases that ratio by incorrectly quoting us as saying that a Saskatchewan technique of installing superinsulation while re-siding a frame house costs $34,000; we actually say this is the extra cost beyond the cost of re-siding alone.) Second, careful shopping is vital. Ausubel could, for example, insulate his windows as well as triple glazing at less than a tenth the cost, using two layers of flexible acrylic Climatic Change 5 (