I've been spending a lot of time recently thinking about lighting, because I'm writing a book about green lighting, which will be out this fall. I've been busy approving layouts. Green lighting is a very exciting set of technologies, because it provides some of the quickest paybacks of any energy efficiency upgrades, it is easy to do, and it can improve productivity and comfort.
There's been a lot of excitement about LEDs (light emitting diodes) recently, and some hot new bulbs are due from major manufacturers in the near future. They are roughly 90% more energy efficient than regular old incandescents, they last for tens of thousands of hours, and they produce less waste heat, meaning they don't contribute to summer cooling loads. LEDs also can come in many colors, and they can be rapidly switched. In fact, chances are good that you are looking at them right now, since many serve as backlighting in computer displays.
LEDs are awesome, and their prices are dropping, though right now CFLs and other fluorescents are a better buy for most homeowners who don't have super-heavy lighting needs. Yes these bulbs have some mercury in them, but that is dropping, and there are precautions you can take, and do be sure to dispose of them properly. However, also don't panic. There is much more mercury in other common products (thermostats, thermometers, electronics, switches), and I interviewed experts in the book who calculated that you'd receive more exposure from eating a seafood meal than is likely from a broken CFL.
