Lighting is responsible for about 7% of the carbon emitted by the U.S., and yet nearly all the lighting in buildings comes from technologies that are 5% to 30% efficient, leaving vast room for improvement. Consider for a moment how that compares to other energy users in a building—the energy conversion efficiency of heating is typically 70%, while electric motors are 85% to 95%.
That’s why there’s so much interest in LEDs, which are just a fraction of installed lighting sources today but expected to make up 80% of the general illumination market by 2020. Today LEDs are 20% to 30% energy efficient, but that’s improving at a rapid pace. There are also design and control advantages to LEDs that increase the overall efficiency of the system. However, the upfront cost is still much higher than traditional lighting technologies, and many manufacturer claims about the longevity of LEDs have yet to be seen in real-world applications.
But the buzz about LEDs is only getting stronger. Much like Moore’s Law for integrated circuits, Haitz’s Law says that process optimization is cutting the cost per lumen of LEDs by a factor of 10 every 10 years while the amount of light …
