Wednesday, August 18, 2010

One LED Light Bulb

The next time you go to buy light bulbs, you might find LED light bulbs for sale. At least five manufacturers have promised to have products in stores before the end of the year, and there must be others I have not heard about yet. LED light bulbs will be in stores not because they suddenly exist, but because the price is falling below $50, the point at which consumers will start to take them seriously.

An LED light bulb might save you $300 or $1,000 in electricity over its 40-year lifetime compared to a traditional incandescent light bulb. That might make it sound like a great investment. On the other hand, with a price between $20 and $50, it will surely be the most expensive light bulb you have ever purchased.

So buy just one. Put it in the room where the lights are on for hours every day, such as the kitchen or bathroom. Or get one that is only half as bright (at a lower price) and use it to light your desk or the TV room, where you don’t need so much light.

Buy just one because if you replace a light that is on for hours every day, you get the fastest return on your investment. In 5,000 hours, an LED 60-watt replacement light bulb will use about $6 of electricity where an actual 60-watt bulb (with two replacements) would use about $45. That is roughly your payback period, depending on how much you pay for the light bulb and how much you pay for electricity. If there is a light you use for 6 hours a day, the payback period could be 2 1/2 years, making the LED light bulb a very good investment in financial terms. But other light bulbs are on 2 hours a day or less. The payback period is longer. A long-term investment in those light bulbs isn’t such a good investment — not till prices fall quite a bit more.

And prices will fall. The other side of the financial calculation for LED light bulbs is that the price will fall and the efficiency will improve. The price of a 60-watt equivalent white LED array fell from $800 five years ago to $80 at the beginning of this year, and there is every reason to expect that prices will fall some more. LED light bulbs are expected to last about 40 years. No one really knows, but the red LEDs from the 1970s are still working with little sign of decline. This makes LEDs a long-term investment. It’s risky to buy them all at once, especially now when your payback period is more than two years. The people who replaced all their light bulbs with CFLs two years ago wasted their money, when compared to their laggard friends getting twice the energy efficiency by buying this year’s LEDs. CFLs are thought to last 10 years or longer (I still haven’t used one up, so I don’t really know how long they last), and it’s hard to just throw them away less than one third through their useful life. But anyone who replaces all their lights with LEDs this year will face that same situation around 2016 — and this year’s LEDs may last until 2050. You reduce the risk of getting stuck with the wrong investment by averaging out the investment over a period of time, and this logic applies to lighting too.

If you want to wait till next year, I won’t argue with that. But if you want to find out what it’s like to spend about $30 and reduce your electric bill by about $1 a month, go ahead and buy one LED light bulb, and start saving money now.