JAN 07

For only 22% improvement? Is article accurate?

So if the old tech lights consumed e.g. 100W each, with the new tech lamps you gain ~25W, that is in 40 hours you save 1KWh ~ 8 cents.
So, your return of capital will be in (380/0.08)*(40/24) ~= 8,000 days ~= 21 YEARS ???? (actually less if you take into account that LED lifespan is bigger). These people know how to plan ahead!!?!

NO WAY!!

Don't forget, the Pentagon also keeps backup generators to run the lights, among other things, if the power goes out. The cost of maintaining sufficient generators and keeping the fuel on hand will factor into the cost. Also, the air conditioning requirements will be reduced. Don't forget that you need to factor that into your costs.

EV is right. When you factor in marginal A/C costs, you're probably down to a 10-11 year payback, and that doesn't include A/C maintence and capital costs saving by having a smaller load. remember that 90% of incandescent energy goes to heat, which then has to be handled by the A/C.

The longer LED life means fewer labor costs for replacement, and labor costs are only going up.

I would say the payback is probably

The Pentagon is not currently using incandescents, they are using Flourescents. However, the replacement costs are going to drop with the longer life of LEDs over Flourescents as you mention.

Don't forget about the direct cost of bulb replacement (cost of the bulb) and the the labor to install the new bulb.

Don't forget about the direct cost of bulb replacement (cost of the bulb) and the the labor to install the new bulb. --sorry I can type today!!

The new lights use less energy and provide better lighting. Seems like a win-win! Hopefully more big purchases like this help drive the price of these light fixtures down so more businesses can afford them.

All points everyone makes about maintenance cost and HVAC loads and better lighting are all great. Another point to mention (and I see I'm about 4 months late in adding my 2 cents), is the ability to digitally control the lights. We represent Cree and they have great quality fixtures, but one of the selling points of LED lighting is that it's dimmable, out of the box, no special ballast, nothing to change out. This means, the Pentagon could put in a digitally controlled system, using these fixtures, that gives them the ability to take advantage of daylight harvesting (sensing when daylight is present and having fixtures automatically dim to maintain a preset light level), adding occupancy sensors that would drop light levels, say to 50%, when nobody is there (or 0%) and have them instantly come to full when space becomes occupied. And that is just the tip of the iceberg when it comes to lighting controls. If anyone out there is interested in LED lighting and is looking, Cree LLS is a great company, has great products and they look more impressive in person than you could imagine. Their 6" dowlight is the best, affordable, an all-around industry leading, fantastic fixture.