Here on the final day of our LED exploration, I get down to brass tacks: the economic and ecological arguments for switching from incandescent to LED. And beware: I use math and logic.
LED Economics
I get it.
An incandescent bulb cost less than a dollar.
An LED bulb costs $25-plus.
Once you recover from LED sticker shock, no one would blame you if you did an about face and promptly plopped an incandescent into your shopping cart.
But wait - consider the following long-term cost-benefit analysis, which concludes that buying a $25 LED represents a substantial cost savings over an incandescent for CFL.
First, there's the replacement cost.
An incandescent bulb will last 500 to 1000 hours; a CFL will shine on for around 8,000 hours.
An LED, however, will light for 25,000-plus hours -maybe close to 50,000 hours as technology improves.
That 25-1 or higher LED v. incandescent lifetime ratio is nearly exactly as the price ratio between the two, which means you'll spend just about the same amount to keep one fixture illuminated - except you won't curse under your breath when an incandescent bulb blows and you're forced to go scurrying around the utility closet to find a replacement bulb and, failing to find one, scurry to the store to buy more bulbs, 25 more times per lighting fixture or lamp.
And, just like any new technology, LED bulbs will and are getting cheaper and lasting longer, such as this prize-winning Philips 60-watt equivalent. Incandescents and CFLs, as a result of having to become more power efficient (see Part 3: The Dimming Dilemma), are actually rising in price.
Then there's the electricity you have to pay to light the bulb.
According the U.S. Energy Information Administration, we pay an average of 11.54 cents per kilowatt hour (your price depends on where you live; find out how much power costs in your locale here). Let's round that figure up to 12 cents just to make the math easier, and we'll use 100-watt equivalents to compare.
Here's a formula I've found for figuring the cost of running a light bulb I found here:
wattage x hours used ÷ 1000 x price per kWh = cost of electricity
Let's say you burn a bulb for five hours a day. At 12 cents a kilowatt hour (kWh), that's 12 times 100 watts times five hours - that's 6 cents a day to run one lamp.
Let's say you burn that 100-watt lamp for five hours a day around 200 days a year. That's $12 a year to power that one lamp. Over 25 years, you'll spend $300 to power that one fixture.
For a single LED, your power costs over that same 25 years is a quarter of that, or around $75 - a savings of around $225.
Okay, you're saving less than $10 a year in power costs with LED - but that's just one bulb in your house. How many incandescent bulbs do you have in your home and how many hours a day do you keep each lit? Now you do the math. You could save $30, $40, $50, $100 or more a year on your energy bill by switching to LEDs, plus achieve piece of mind that when you flip the switch, the light will light.
But if dollars don't convince you...
Ecological
Finally, I appeal to your conscience concerning conserving the resources of this small and vulnerable blue ball we all share.
Here are three ways an LED is better for the environment.
The first is obvious: less energy usage. Did I mention that an LED bulb uses a quarter of the power needed to burn an incandescent bulb?
How much power would we save? Think about how many homes there are in the U.S., how many incandescent fixtures there are in each home, and how if everyone replaced each incandescent with an LED - well, my math isn't great, but I'll bet that represents billions of kilowatt hours saved.
And that's just residential. Commercial electric needs are nearly seven times that of residential, and industrial electrical needs are more than 70 times higher. (This statistics Web page of the aforementioned U.S. Energy Information Administration is chock full of electrical usage statistics.)
To paraphrase Senator Everett Dirksen, a billion kilowatt hours here, a billion kilowatt hours there and soon we're talking real power savings.
And, of course, most of our power plants are powered by coal, which means tons of carbon dioxide spewed into our atmosphere speeding global warming. If we chucked our incandescents and CFLs in favor of LED, that's less coal needed, which means less CO2 spewing. (Although we'll probably use all that saved electricity to charge our electric cars, so maybe the whole thing evens out...)
Second, since we need one LED to replace 25 or more incandescent bulbs, that means less packaging materials are needed to pack up bulbs, lower distribution costs, i.e., trucking to bring LED bulbs to stores, and lower waste costs once the store unpacks the bulbs for sale and chucks the boxes, and we chuck the packaging for the bulbs at home.
Finally, LED bulbs are more recycling eco-friendly. You won't replace them too often so there'll be fewer of them to worry about recycling, and the LED chips can be recovered and reused.
Plus, who knows what marvelous recycling technology we'll have in 25 years when the first LED bulbs go bad.
This ecological argument is purposely drawn in broad strokes. If you want the whole technical LED life-cycle story, check out this February 2012 study, "Life-Cycle Assessment of Energy and Environmental Impacts of LED Lighting Products, Part I: Review of the Life-Cycle Energy Consumption of Incandescent, Compact Fluorescent, and LED Lamps," from the U.S. Department of Energy.
Final argument
Let's review our LED FAQs and LED pro-con switching arguments.
Incandescent Equivalency: Think lumens, not watts. 60-watt incandescent equivalent=800 lumens, 75-watt=1100 lumens, 100-watt=1600 lumens.
Quality of Light: You can get soft, white incandescent-like light from an LED, and soon, 100-watt and likely three-way LEDs.
Aesthetics: Okay, LEDs are ugly, but you can hide them behind a lampshade. Just make sure you get one that glows all around, not just upward.
Dimming: Okay, a definite con.
Legislative: Incandescents aren't going away and the government is not forcing you to buy LEDs. They just want to save energy.
Economics: LEDs cost more upfront, but much less in the long run once you factor in energy savings.
Ecological: LED require a quarter of the energy of incandescents. Fewer LEDs means less waste when they finally stop working 25 years from now, both packaging and the bulbs themselves.
I'm not sure I'd run out and replace all my current incandescent or CFLs with LEDs - why prematurely add to the waste?
But, unless you have a home filled with dimmer fixtures, there is no reason why you shouldn't replace each burned-out incandescent or CFL bulb with an LED.
Related:
All About LED, Part 1: Bulb Basics
LED Bulbs, Part 2: How Soft is the Light?
All About LED Bulbs, Part 3: The Dimming Dilemma
