Conversely, what then could be more wasteful, more undesirable, and more irrational than negating a large share of these conversion gains by wasting them? Yet precisely this keeps on happening—and to indefensibly high degrees—with all final energy uses. Buildings consume about a fifth of all global energy , but because of inadequate wall and ceiling insulation, single pane windows and poor ventilation, they waste at least between a fifth to a third of it, as compared with well designed indoor
