Science and society test X: Energy conservation

United States energy consumption has remained essentially constant at about 80 exajoules/year (75 quads/year) since the oil embargo of 1973–1974, while the GNP in constant dollars has increased by about 30%. This article will discuss the physics behind some of these improvements in end‐use efficiency in such areas as: (i) buildings (scaling laws, ‘‘free‐heat,’’ superinsulated houses, thermal storage in large buildings, off‐peak cooling), (ii) solar energy (passive, photovoltaics), (iii) utility load management (‘‘smart meters,’’ capital recovery fees, voltage control), (iv) appliances (life‐cycle costs, refrigerators), and (v) lighting (isotopic enhancement).