ABSTRACT
A physicist’s first thought on hearing the phrase “energy conservation” is probably: “How could it be otherwise; energy is always conserved!” But of course we are here using the phrase in a different sense of how energy is used by humans and efforts to reduce the amount we use. The two concepts of energy conservation and efficiency are closely related, and both are worthy of support, but they have somewhat different connotations. Efficiency involves using less energy to achieve the same ends, while conservation puts the stress on simply using less energy, even if we have to compromise on the ends. Efficiency generally involves a technical solution, while conservation involves a behavioral one. Thus, we can conserve energy in the home by turning down the thermostat and wearing a sweater, or we can use energy more efficiently (and use less of it) by having a programmable thermostat that lowers the heating or cooling system at the times we normally are not at home. Of course, there is in this case every reason to follow both courses-the first action (conservation) requiring a small sacrifice, and the second one (efficiency) requiring neither behavioral change nor sacrifice-except perhaps learning to use the programmable thermostat! Although efficiency and conservation are often mutually reinforcing, they can sometimes be seen as being in conflict, depending on one’s worldview.
