Wednesday, December 12, 2007

It Really is an LED Christmas Season

Tom Griffiths
November 29, 2007...For those around the world that celebrate Christmas or coincident holidays by stringing lights about the house and yard, it seems pretty clear that the decorative buzz is about LED lighting. The year 2007 seems to be the one where LED Christmas lights have gone from novelty to "common sense". Interestingly, they are doing so in spite of the energy payback for LED versions being something on the order of 4-10 years when a 1-2 year payback is often all the consuming public can really wrap its arms around. Frankly, if we set aside some of the local government incentives that we're seeing, I don't think it yet has a lot to do with the real payback these tiny solid state lighting alternatives are providing.

For starters, here is a quick numbers run from the resident economist. Incandescent mini-lights at 40 watts per string, running 5 hours per night, for 30 nights, adds up to an operating cost for the season of at least $.60/string (assuming a $.10/kW electricity rate... you can nearly double that in some places). Incandescent C7s that are most often used for outlining the roof of a house run more like 175 watts per string suggesting a seasonal operating cost of at least $2.50/string. One year, when we fully outlined the house in the C7s, we enjoyed better than a $200 uptick in the monthly electric bill, as well as the exciting sounds of more than one airplane making a go-around when they realized we weren't the nearby runway (at least that's my version of the story and I'm sticking to it). By contrast, the comparative LED strings will typically run at 4 watts or less, which puts them somewhere around $.06 for the season. That's close enough to free that we might as well just consider the cost of the string as the only issue. As far as the acquisition costs, $10-$15 seems to be the current "on-season rate" for something in that typical 25-foot (3-meter) length.

Since us "lighters" are used to buying a certain number of replacement incandescent strings each year, other than the 1 or 2 impulse strings, I tend to suspect most serious lighters hit the before- and after-season sales, picking the strings up for $1 to $2. Preferring simple formulas over precision, I would round that to being "nearly free" compared to the LEDs. Nearly free light strings are then head-to-head with virtually free operating costs. The $.60 to $2.50 per string "old" operating cost stacks up against a $10-$15 "new" LED purchase cost. Depending upon your choice of big or small incandescents, the payback is 4 to 20 years! (On the small incandescent string, the typical 2-3 season lifetime shortens the 20 to maybe 6 or 7 years).

While there is nothing shameful about a 4 year payback, it is just not typical of your average Wal-Mart or Home Depot holiday consumer to consider a payback period at all, much less one of that length. Lots of time, and marketing dollars have been invested on "awareness initiatives" to sway consumers to consider CFLs as replacements for Mr. Edison's original invention, and that relatively short payback has only recently begun to gain real traction in the US. So what's driving the willingness to spend $10 more for a simple light string? Two guesses are offered.

The first guess is that they are actually bright enough, believably long-lived enough and, most importantly, finally priced where they don't seem expensive (call it "cheap enough"). With the on-season price of the incandescents often around $5, a consumer can look at "the usual" few strings they'll need and reach the conclusion that "the extra $5" per string is probably worth it to start to eliminate the seasonal dead-bulb hassle. That's a bit of an impulsive conclusion if we accept that many of those consumers would really be more likely to pay the off-season price for those needed strings during any given year, but the holiday season is certainly one that is given to impulse shopping, so why not go with the flow. The 'by the way' to this guess would have the shopper adding the thought, "Oh, and I've heard they will save me a ton in electricity costs."

The second guess is that the energy saving story that accompanies LED and solid state lighting is sinking in, due almost exclusively to their presence in the more ubiquitous daily applications that work including nightlights, flashlights/torches, automotive CHMLs, tail-lights and traffic signals. The resulting impression would seem to be somewhat along the lines of, "I'm seeing those LEDs everywhere... they must really be saving some money somehow or I wouldn't keep seeing more and more of them." Add to that a strong perception of rapidly increasing energy costs of all types (for the US, the rise in gasoline prices is a strong driver for that perception), and it likely just takes a different perception path to arrive at the same "saving me a ton" conclusion.

Either way, what does it mean for the solid state lighting industry? First, it means LEDs are doing their jobs and the technology is proving itself in key applications that are causing a recognition with the majority of the the people out there. Second, the consuming public is beginning to make the logical jump that if an LED works well for lighting something up in several different types of applications, it will work well in the next application they find it in. Third, there's more of it to come. We're just at the tip of the tip of the iceberg in the start of a wider scale adoption of LED-based lighting technology. Fourth, there is still plenty of room to make things more difficult by moving too fast into applications where they might not quite be ready, such as Edison screw-based incandescent replacements. Pushing something junky into the market will erode the goodwill built up from #1 and disrupt the otherwise clear thinking that results in #2, and possibly disrupt the perceptions that is leading impulse consumerism to actually follow a desirable longer-term path. Niche-to-niche works!

Tuesday, December 11, 2007


Python + numpy + scipy + matplotlib