The sad truth is that if you want to learn about or work on energy efficiency, you need to understand the world of finance. Many of us in the energy/environment field (especially those working on policy) are more comfortable talking about efficiency ratings than credit ratings. But implementing energy efficiency projects at the scale we need will require large sums of money moving through our financial system.

Government programs are all well and good, but they are necessarily limited by the amount of money we can convince politicians to spend, and even the most generous programs can only scratch the surface. For example, the Department of Energy’s Better Buildings program is aimed at retrofitting homes for energy efficiency and has