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CREE LR6 6" recessed downlight

Light-emitting diodes, better known as LEDs, are all around us--those little red or green indicator lights that blink at us from our stereo equipment, most new traffic signals, and virtually all new exit signs in commercial buildings. And if you've been to Times Square recently, you've seen way too many LEDs being used for advertising! We've all seen colored LEDs; what's new is the use of white LEDs for indoor lighting.

7/1/09 Update: If you're looking to keep up to date on LEED 2009, I recommend checking out our own LEEDuser.com, which was recently launched Since the Green Building Certification Institute announced big changes to the LEED Accredited Professional (LEED AP) program (chronicled here), a few other key items have come out. First, the final date to

HID lighting at Fenway Park in Boston.

Three recent columns provided a brief history of lighting, an overview of fluorescent technology, and a look at the challenges of improving streetlights. Following a side trip into the issue of "passive survivability," I'm returning this week to illumination with an overview of high-intensity discharge (HID) lighting.

From the Father of Green Chemistry to that guy from This Old House, a couple dozen videos of speakers and presentations from Greenbuild '08 have been posted at Greenbuild 365, "USGBC's interactive green building learning portal." Among th

"Smudge" — more here Happy holidays!

Some homes in New Orleans were without power for months as a result of hurricane Katrina in 2005.

The ice storm a week-and-a-half ago illustrated, all too clearly, the vulnerability of our homes. Hundreds of thousands of homes in New England lost power in the storm, which deposited up to an inch of ice on trees the night of December 11th, and tens of thousands were still without power a full week later, despite heroic efforts by utility crews.

Twice each month, BuildingGreen publishes an email news bulletin with current news and product information briefs. Sign up here — it's free. We will never share or sell your email address, and you may unsubscribe at any time.

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Mercury vapor light. Mercury vapor is the oldest type of high-intensity discharge (HID) lighting.

Last week we took a look at fluorescent lighting, which is dramatically reducing our energy use for illuminating indoor spaces. This week we'll cover mercury vapor lighting, which is the most common outdoor lighting in many of our towns.

Fluorescent lamps have electrodes at both ends of a phosphor-coated, sealed glass tube that is filled with a small amount of mercury vapor in an inert gas, usually argon.

Last week, after an overview of lighting history, we examined incandescent lighting--the lamp technology invented by Thomas Edison. Until the mid-1900s incandescent lighting dominated both commercial and residential lighting applications, indoors and outdoors.