December 6, 2006
Lighting is becoming much more efficient. Light-emitting diodes (LEDs) are solid state electronic devices that emit photons as they conduct electricity. They do so with great and growing efficiency—so much so that they are beginning to rival the output of common lightbulbs.
The difference? They draw much less current for the photons that they emit. They also generate much less heat than an incandescent source, which produces light by heating a filament until it is white hot. The result is doubly-green: less current draw (less electricity burned) and less heat produced, thus reduced cooling costs for the house lit by LEDs.
They even draw less current than compact fluorescents and do not include heavy metal, such as mercury, or environmentally-damaging phosphors in their manufacture. Finally (perhaps the best bonus) the lifetimes of LEDs are around 50,000 hours—at least 6 times compact fluorescent, and 12 to 25 times that of incandescents. This is the lighting solution of the future.
The downside is that at the moment the brightness of LED lighting is just getting to tolerable levels to be used practically. AT THE MOMENT. This will change, and the cost will drop. Meanwhile, we have found a great source of linear LED sources that can be used for ambient soft lighting and accent lighting. Mark Loeffler, our lighting designer introduced us to these fixtures, consisting of a line of white LEDs, driven by a 24 volt source. The light stick is 1/2 x 1/2 inch in cross section, allowing it to be hidden behind moldings.
Because LEDs generate so little heat, and because they have such long life, they can be put in spaces that are difficult to access. We should never have to replace these! I'd like the house to have a complete 24-volt circuit run into every room, but this won't be practical, since each element needs to be attached to its own small transformer for code reasons. Still, there will be a day when all houses have a low-voltage circuit for light generation, using LEDs.
(4) CommentsComment on this Blog
I like what I'm reading. Thanks for the lesson on LEDs. I look forward to the future and using these.
Hey, nice project - and long time, no see.
I'm still in Boston, making LED lighting for a living, so this post in particular caught my eye.
Your analysis of the state of LED lighting is about right - some applications are more practical than others right now. Not so sure that 24V will be the way of the future, though, if only because low power electronic step-down power supplies are dirt cheap when the mfg volumes get high enough, and 120V is pretty well entrenched.