Want to reduce energy demand? Just let the building make the decisions

摘要

Houses built before the turn of the 20th century did not, for the most part, have bathrooms. Ablutions required a cold and dark trip to an outhouse, often perched over a pit in the ground. Yet, within a few decades, the modern bathroom evolved from a novelty into an almost-universal residential fixture. Thomas Crapper's valve-and-siphon design was patented in 1891 and found its way into homes all over the country in the decades preceding the First World War (as well as endowing the English language with a great new word).