Sunday, January 27, 2013

LED lighting and microeconomics

If you believe Michelle Bachmann, the legislated phase-out of the incandescent lightbulb is a facet of an insidious plot to destroy freedom [1] [2] [3]. We reserve the right to be as idiotically wasteful as we please!

You can guess from my sarcasm that I don't give that much creedence. But sticking to the incandescent is, with all apologies and respect to Thomas Edison, a downright stupid thing to do. Why? It's more expensive. Reserving your right to be as idiotically wasteful as you please is also reserving your right to throw away money and needlessly contribute to the ruination of our one and only home. Hoarding 100-watt bulbs in your basement? Congratulations: you have just tied yourself to a decade of spending much more than necessary to light your home. You are doing no one, particularly our nation, our freedom, and our planet, any favors. I'll get to the numbers in a minute.

I can understand the reticence. Look at a typical 60-watt incadescent - it costs less than a dollar. Burns out: swap it and go on with your life. Now compare to what had, until recently, been the primary alternative - the compact fluorescent. I have paid to replace incandescents with CFLs in three residences over the last decade - a few dozen bulbs from different manufacturers at varying price points. The energy savings are undeniable. The steady-state color is pleasant from most bulbs. The mercury content didn't bother me much; it was a manageable inconvenience. I've never had much use for dimmer switches.

But, despite my environmental leanings, I had my gripes with the CFL. The turn-on time was the biggie for me. Some of my bulbs came on to full brightness immediately. But many, and unfortunately some I used most often, would be sluggish. Coming down to the kitchen in the pitch black of a January morning, with the thermostat showing 55F, flicking the switch would spark a weak, sickly pale, purplish green glow, which would take a minute or more to demonstrate itself worthy of being called light. There were probably better bulbs out there, but at $5/ea, it's not something I could change out casually. Besides: what to do with the old bulbs? yes, I could recycle them, but they are still perfectly serviceable and represent a significant "sunk energy" cost in their manufacture.

But I am very optimistic about the future of lighting: LEDs. I've tinkered with LEDs in one form or another since college. I've even incorporated them into Brynna's nightlight. I've followed the development of the LED lighting industry from niche to mainstream. I would say that the products available now, from reputable vendors, are ready for widespread adoption for the uncompromising masses. A decade from now, I'm willing to assert, in my capacity as an engineer, that there will be little justification for buying another incandescent.

And I'm willing to put my money where my mouth is.

I will be the first to admit that digital photography is a difficult way to judge lighting. My own equipment is not exactly stellar for this task either. The camera is not an eye. Still, bear with me.

Which are incandescent? Which are CFL? Which are LED?

The answer is that there are no incandescents. The two bulbs in the hanging fixture are CFLs. The recessed lights (seven in the kitchen and pantry) are LEDs. You are seeing them here at full brightness. Were I to turn them off, let them cool for a few hours, then return and flick the switch, the recessed lights would be back at that full brightness in the blink of an eye. That's the big sell for me: the instant-on. The fact that they do not contain mercury, are less energy intensive to produce than CFLs, last longer, use less power for equal or better light, and are entirely compatible with dimmer switches are nice bonuses. And this technology will only get better and cheaper.

The recessed lights you see here are sold under the EcoSmart brand at Home Depot and retailed for $35 apiece. I also managed to score a $10/ea rebate from the local utility (take that, RGGI haters). They replace the entire recessed can, but screw into the standard socket at the back. Installation took all of three minutes apiece.

Now for some numbers. These bulbs are rated for 30,000 hrs lifetime. Given how they are used in our home, that works out to a decade or two. The rebate I got is not universally available, but you can probably find something in your area. Let's call the cost $30 apiece. That works out to an amortized cost of $0.001/hr. To produce the equivalent light of a 65-W incandescent, these pull about 10 W. If you take my monthly electric bill and divide by the energy used, it runs about $0.18/kWh. All told, the operating cost per bulb works out to about 1/3-cent per hour.

Compare to an incandescent. A little searching will find a 65-W PAR 30 bulb retailing for about $2. It will last upwards of 2000 hours. This yields an amortized capital cost of, TADA!, $0.001/hr. In other words, hour for hour, the new LED fixture costs the same to purchase as the conventional incandescent. The LED bulb uses 1/6th the power to produce the same light, and so it costs 1/6th as much to operate.

This is a clear win. Over their lifetime, I estimate each LED fixture will save me $100-$200; about $1000 just for this one room.

The comparison to a CFL is a bit tricker and less clear cut. A CFL bulb will run perhaps $10-15 (depending on quality), last about 1/2 as long, and use a touch more power than an LED. Depending on how you work these estimates, the CFL can be the cheaper option in terms of Total Cost of Ownership. However, as I mentioned above, I have grown dissatisfied with CFLs. CFLs may be great in most respects compared to incandescents, but they now seem like a poor compromise compared to what's available now in LEDs. So why aren't we all running out to the local big box store for a mass conversion? There are plenty of reasons. Consumer inertia is one reason. By that I mean that consumer behavior is difficult to change. Plenty of people (my electrician included) stick with incandescents as the default choice because of their consistency, long standing existence, and low upfront cost. Those who were inclined towards CFLs on their merits have largely already converted, and aren't too anxious to junk that investment. Other consumers have been burned (figuratively) by CFLs for a variety of reasons; deserved and otherwise. Lots of people rent, and why make capital improvements in a place you don't even own? I also admit that, as an engineer, these kinds of calculations and considerations are second nature to me; most people simply cannot be bothered. That's OK to an extent: there are plenty of matters that, being outside my area of expertise and experience, I simply cannot be bothered with. Cost is probably the biggest hurdle. I've converted the kitchen because it is the lighting we use most frequently. It's the place with the greatest room for improvement over CFLs. The PAR30 form factor (i.e., recessed can) provides a more favorable economic and aesthetic case compared to the usual bulb. Even so: I dropped a few hundred dollars for this one room. Sure, they'll save lots of money over their lifetime, several times what I've put in, but it's still a lot of money. There's a decent chance, too, that we won't even live in this house long enough to recoup the investment.

The way that I look at it is the way that I think many people will eventually come to look at it - as a capital investment. Think of all the important components in your home: the heating and cooling equipment, the toilet, the refrigerator, the stove. Why shouldn't we start to view lighting as another big ticket item along these lines? When a lightbulb's lifetime can be measured in decades, it has moved out of the category of consumable items like toilet paper, razor blades, dish detergent, automotive oil. Instead, it has become a piece of equipment: something that is installed in the home; a fixture.

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