From homes, to offices, to factories, to schools, and many other kinds of buildings, the places we inhabit cost energy. They cost energy to build, and to heat, cool, and to light, and they also represent one of the easiest, most straightforward ways to conserve energy. From construction to insulation, to window placement, to geothermal heat pumps, there are a myriad of ways to lower the energy cost of buildings, saving both money and emissions. 

Bio-inspired design could lead to more efficient windows:
Scientists mimic biological temperature control systems to develop windows that keep heat in in the winter, and cool things off in the summer.