Sunday, August 22, 2010

The Great Bulb Debate

I recently read an article on LiveCheap article about "How to Cut Your Electricity in Half." As with so many of these articles, the number one suggestion was to replace incandescent light bulbs with compact fluorescent lights (CFLs). This suggestion sparked a couple of comments to the effect that CFLs are (1) hard to dispose of safely, (2), dangerous if they break (one poster suggested that you would "require a HAZMAT crew to come and clean if God forbid you drop one and break it"), and (3) inferior to the newer, still-more-efficient light-emitting diode (LED) bulbs.

I had previously encountered similar suggestions in a Dollar Stretcher article by Rich Finzer, "CFL versus LED." Finzer claimed that CFLs "are extremely fragile, perform poorly in cold locations, and are nearly impossible to recycle," and also that they "require a warm-up period before reaching full illumination." He went on to claim that LEDs were "a smarter choice" because of their longer life and ultra-low energy use.

After reading his article, I submitted a post on the Dollar Stretcher forum debunking his claims. I pointed out that Consumer Reports had addressed these claims in a recent issue (you can read the "myths and realities" on the magazine's blog). It said that most modern CFLs come on instantly and reach their full brightness within about 30 seconds (a delay that I hardly even notice with mine; even at less than full brightness, the bulbs are plenty bright enough to see by). It also points out that unbroken CFLs are accepted for recycling at all IKEA and Home Depot stores, as well as some Ace and True Value stores, and that broken ones, while they do pose a health hazard, are not nearly so difficult to clean up as some people think. (The EPA provides detailed guidelines at this site.)

Then I went on to tackle the question of the economics of CFLs versus LEDs. There is no denying that in terms of bulb life and energy use, LEDs are greatly superior to CFLs, just as CFLs are to incandescents. The only question was whether the energy savings would be enough to offset the much higher initial cost of the LED bulbs. I crunched some numbers and concluded that in terms of their lifetime cost, an LED bulb came out just barely ahead of a CFL--but it would take most of the lifetime of the bulb, which could be more than 15 years, to pay for itself. I concluded that while LEDs might indeed be the bulbs of the future, it was worth waiting for the price to come down before making the switch.

After reading the Live Cheap article, I decided to revisit these figures and see if the price of LEDs had come down enough in the past two years to make them cost-effective. I found that the cost of an LED bulb has indeed fallen—but so have the prices of CFLs. The price of incandescents has actually gone up, but so has their lifetime. Here are the updated figures, based on a search of products available at

1. GE 60-watt incandescents: 4 for $1.99, estimated lifetime 1,500 hours

2. GE 13-watt CFLs, claimed equivalent to 60W incandescents: 8 for $6.99, estimated lifetime 12,000 hours

3. EagleLight Nichia 6-watt LED, claimed equivalent to 60W incandescents: $43 each (with free shipping), estimated lifetime 35,000 hours. (I had to go to the manufacturer's page to get this information.)

The other thing that's changed is that my utlility's price for electricity has dropped by half a cent per kilowatt-hour. Between that and the changes in price, the lifetime costs of all three types of bulbs have dropped significantly. Over the course of 35,000 hours of use, you would pay for:

1. 23 incandescent bulbs at 50 cents each ($11.66) and 2100 kilowatt-hours at 17.5 cents per kWH ($367.5): total $379.16

2. 3 CFLs at 87.4 cents each ($2.62) and 455 kilowatt-hours at 17.5 cents per kWH ($79.63): total $82.25

3. 1 LED at $43 and 210 kilowatt-hours at 17.5 cents per kWH ($36.75): total $79.75

So once again, the LED is just barely ahead of the CFLs on lifelong costs. (Of course, there are other factors that might make LEDs more desirable, like the fact that they'll last nearly forever. Thirty-five thousand hours in a fixture that's used 5 hours a day is over 19 years. That might make LEDs practical in fixtures that are really, really inconvenient to change a bulb in.)

I'm keeping my CFLs for now and waiting for the price of LEDs to drop more (as I'm sure it will). After all, I paid $25 for my first CFL years ago (and this was an old-school CFL, bulky and not as warm-toned as an incandescent)—so when LEDs get down into that approximate price range, I think it'll be worth springing for one.

However, one thing these figures really reinforce for me is what a small amount of electricity we're talking about here. Even the relatively power-hungry incandescent bulb is using only $367.50 worth of electricity over the course of 19 years, or about $1.60 a month. Someone who is hoping to cut his electric bill in half by switching out a few light bulbs is probably in for a serious disappointment.

Postscript: Just spotted this entry on the Consumer Reports blog about a new LED bulb being sold at Home Depot that costs only $20. However, this model is intended to replace a 40-watt incandescent, so it doesn't fit neatly into my comparisons above. It's certainly cheaper over its lifetime than a 13-watt CFL, but it also gives less light. I'm not planning to buy any, but I'll be keeping an eye out for higher-wattage versions.

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