ABSTRACT
In past centuries, the relative lack of resources to construct and maintain buildings meant energy-conservative and locally sourced inputs were the norm. From Imperial Rome until the nineteenth century only the wealthy could afford thermal baths or orangeries. Since the industrial revolution, but particularly in the past 100 years, the twin phenomena of more widely-diffused wealth and relatively cheaper energy have resulted in widespread increases in energy use. The cost of maintaining a high-efficiency artificial light source is one thousandth of that which a tallow candle represented 120 years ago. Such reductions in proportional cost, and greater affordability, apply not only to energy but to materials produced or transported using energy – which includes all building materials. As a result, the cost of building and running buildings has fallen many times over, and for some decades it appeared unnecessary to consider every design issue from an energy-cost viewpoint.
