Lumen Depreciation

As LED technology continues to evolve, so too grows the efficiency and lifespans of LED lamps. Because LEDs have such long lives (estimated at 35,000 to 100,000 hours), it’s rather challenging to measure precisely how long they really do last — few groups have the patience or resources to measure an LED in various environments for 5 or more years. However, the National Institute of Standards and Technology (NIST) is currently working on such a project.

Without a predictable failure point, manufacturers decided to define LED life as the amount of time it takes for the light to fade to a certain percentage of its original strength. “Lumen depreciation is widely understood in the lighting community and is not unique to LEDs. But it doesn’t come into play when you have a light source that only lasts hundreds or thousands of hours, as with incandescents. On average, incandescents fail before the eye notices a difference in their output,” says Philips Marketing Communications Director Steve Landau.

People in an average office setting can’t tell there is a change in illumination until a lamp has dropped 30% in output. So it is not objectionable to wait until the LED is at 70% of its original spec before you replace the lamp.

This designation is represented by the letter ‘L’ followed by a set of numbers such as:

L70 = time to 70% of original light output. There are other ratings, but this is the most common rating and is universally accepted as the standard to measuring LED life.

For colored accent and exterior lighting, the lumen acceptable lumen drop-off threshold is often considered to be 50%.

Still, even these numbers are highly variable depending on how and where the LED was operated. Things that may influence the LED’s life are line current, ambient temperature, the type of luminaire and the quality of the material used. These differences make defining a LED’s service life even more challenging, since the lamp’s environment can drastically influence its lifespan.

Simply, we can’t determine the service life of an LED without considering its housing and application. This is the major reason why the NIST is conducting their LED study. They are monitoring LEDs in various scenarios with the goal of uncovering a reliable method of projecting how long LEDs will last.

HOW LONG is 100,000 HOURS?

Whether you believe 100,000 hours is realistic or not, I’ve included a chart to make understanding the life of a 100,000 hour rated bulb easier.

Hours of Operation:  100,000 hours is:
24 hours a day                11.4 years
18 hours per day             14.8 years
12 hours per day             22.8 years
8 hours per day               34.2 years


Although the lighting industry is still learning about the efficiency of LEDs, what we currently know holds real promise for major energy savings in the future. And while the LED bulb you pick off the store shelf may not entirely live up to its 100,000 hour rating, it will certainly outperform most traditional bulbs.

2009 KBIS Product Showcase

Guest post from Jamie Goldberg

These are some of the products I spotted at the 2009 Kitchen/Bath Industry Show that I thought fellow KitchAnn Style readers would enjoy. As I always check this blog for the latest and greatest, it was an honor and a challenge looking for new things that would interest KAS readers.


Toto can always be counted on for great product introductions, and this year was no exception. My favorite releases were the Luminist series of resin lavs that could be lit from below with LEDs or even fluorescents. Your lav could be illuminated with colored – even changing lights – for a dramatic powder room or master bath. (Night lights never looked this good!)Another Toto favorite of mine was the Waza Noir. Not only is it sculpturally beautiful, its finish is as smooth and touchable as velvet.


Kohler has redefined the white fixture. And the results are soft, matte and elegant. Its new Honed White lavs and toilets feature a gentler-toned finish that lends itself beautifully to spa style baths. Rather than the traditional, glossy paper look, Honed White looks like Haagen Dazs vanilla bean ice cream. KitchAnn Style readers may particularly enjoy the new Reve contemporary bath suites in this luscious new finish.

Kohler also reintroduced gold to the designer’s palette with its Vibrant Moderne Brushed Gold. It’s got a polished companion, too, but I think the softer brushed works best in these hard-edged times.

I was also taken by Kohler’s new Parity bath, which features a richly-stained transfer seat. While this wooden perch makes it easier for someone to get in and out of the tub, it also makes it easier to keep bath goodies at hand, or even add candlelight to your bath.


Many of the top appliance manufacturers stayed home this year. Two, however, brought their A Game. LG introduced a new double drawer French door fridge with automation. If you’ve ever wished for a third hand, this may be the appliance for you. A control panel on the front of the fridge makes it easy to open the freezer drawers without bending or tugging.

Bosch is also making it easier to work in the kitchen. Its new AutoChef Induction Cooktop includes pre-sets for frequently-made foods. I’ve been a big proponent of induction, and I know Ann is a fan of this energy-saving technology, too. One hesitation clients have had is that they’re very comfortable cooking with electric or gas and aren’t sure how to adjust their recipes for induction. This is a good solution, and a pretty sleek cooktop, too.

Robern has brought a touch of technology to the medicine cabinet. Its new Uplift series can hold a flat-screen TV, along with your standard bath fare. Its sleek design incorporates a door that slides upwards, creating a range of new design options.


Design enthusiasts know that great hardware can update your home in a heartbeat. If they’re fans of the world-renowned Clodagh, they might be interested to know that Du Verre has released two new lines of cabinet hardware the famed interior designer created just for them. One is called Primitive. The other is Stacked. Both are fun, quirky and unique, and will definitely update any room they show up in.