LED lighting - a good alternative for residential projects?
Tuesday, July 28, 2009 at 8:19PM We recently had the opportunity to work extensively with LED lighting applications at one of our projects, mainly as an alternative to fluorescents. Working directly with one of the manufacturers gave us detailed insight into what to look for in high quality LEDs, since not all LED’s are alike or suitable for all applications. On our project, we ended up using LED lamps for overall ambient lighting through recessed fixtures, cove illumination, staircase and under cabinet lighting. Two aspects that are especially important in finding good quality LED’s are their color rendering index (which will impact how colors of finishes in the room will appear to the eye) as well as how long they can be expected to maintain their properties.
So are LED applications worth the significantly higher initial price tag?
It depends. Price comparisons must be made not only looking at energy consumption over the lifetime of the lamp, but also consider the application. Besides considering decorative attributes, a specific lighting application may call for a certain amount of light needed (lumens), a certain shape of light, direct or indirect application, a certain color rendering, dimmable lights or not etc. Once the application is clear, alternative lighting solutions that comply with these specifications can be evaluated and what looked like a clear low cost alternative may no longer be one. For example if the requirement for a cove lighting application is to be dimmable, the cost of an installation with fluorescent lights will likely exceed the cost of the same application with LED lights. Certain LED lamps simply have a better color rendering index than the best fluorescent alternatives currently on the market. However, in other applications good quality fluorescent lighting may be just fine and at much more cost effective alternative.
Lastly, from an environmental perspective LED’s have the advantage that once they end up in a landfill they do not contain harmful mercury, which is the major drawback of fluorescent fixtures. So as counties require treating fluorescent lamps as hazardous waste or require recycling, the cost of disposal is another item to consider.
Reader Comments (1)
Incandescents vs. LED vs. Fluorescents: last sunday there was an article in the San Jose Mercury News http://www.mercurynews.com/business/ci_18957004
My comments:
1) The claims of 7-8 yr lifetime for CFLs is shaky. I haven't obtained a clear answer as to whether a) this is based on an extrapolation from continuous operation (switch it on and leave it on until it dies, then multiply its age by the inverse of the average duty-cycle (say 6 of 24 hours or 1/4 ) or b) this is based on a 7-8 year long experiment which involves switching the light on at least once every day. Switching on a CFL is "hard" on it, causing deterioration of the electrodes, the choke and thermal cycling effects on structural components. Now you understand why CFLs burn out in less than 2 years.
2) OK, so the downstream environmental footprint of CFLs is bad (the mercury) and perhaps much worse than LEDs. However, LEDs have electronics, with lots of heavy metals. More important, during manufacture, LEDs, like all other solid state electronics have one of the heaviest environmental loads from mining, purification, water for washing, energy for production, large amounts of oil-based derivatives (polymers etc.) and HUGE amounts of soluble and insoluble chemicals for production etc. While the average manufactured goods have a environmental load of about X30-40, electronics has been estimated at anywhere from X150-500. (See Royte's Garbageland and blog). CFLs, on the other hand, are relatively low-tech, glass from the beach, little to no purification, control is mostly electrical, not electronic, and yes mercury, which is actually one of the easier metals to purify from its mineral state.
So once we include UPstream env. effects (which nobody in the US wants to talk about) it is not at all clear that LEDs are superior to CFLs.
3) Finally, energy efficiency will at most get 10% savings if we extrapolate all fancy technologies etc. The low hanging fruit in the US is to turn things OFF. Considering that the US per capita energy consumption is 40 times the global average and 3-4 times that of Europe, one can potentialy get 60+% savings with lifestyle changes and 0 technology.
Why are we as a nation and culture wasting our efforts on that measly 10%? "Lifestyle changes are hard." But of course they are, doesn't mean they are impossible nor that they shouldn't be done. Also, there is no money in advocating "turn things off", but if have "cylindrical solar power concentrators for photo-voltaic power generation", people will throw money at you.
Thank you for the opportunity to discuss this.