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Upgrade Your Holiday Twinkle Featured on Nov 29, 2010

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Challenge Details

This challenge was originally published on November 29, 2007. We’re about 40x larger for the 2010 holiday season, so let’s deliver a much bigger holiday gift to Planet Earth this time around!


There are few symbols of the winter holiday season as vivid and meaningful as holiday lights. Just when we turn back our clocks, beckoning to our innate urge to hibernate, the holiday lights are illuminated to signal the winter holiday celebration. While there are plenty of opportunities to reduce carbon emissions during the holidays, switching your traditional, incandescent holiday lights to new light-emitting diode (LED) bulbs is perhaps the simplest way to achieve large carbon emission savings without curbing your participation in holiday cheer.

The Carbon Connection
The fact is, by switching to LEDs, you can readily preserve your most garish holiday lighting arrangement and still reduce your carbon impact by 90% compared to last year. And the carbon connection is pretty simple to understand. Every time you flick on a light switch, electricity flows from the nearest power plant which is probably powered by coal, oil, or natural gas. Wherever you can minimize your electricity demand, you will directly ratchet down the carbon emissions from your local power plant.

Compared to traditional incandescent holiday lights, LED lights use much less electricity. An average string of incandescent holiday lights consumes about 500 watts of electricity every hour. In comparison, a similar string of LED holiday lights uses about 50 watts per hour. That’s one tenth the electricity! And that translates into about a 3/4 pound reduction in CO2 emissions for every HOUR you use a string of LEDs instead of traditional lights.

And all that saved electricity translates to saved money as well. Each LED string will lower your energy bill by about $9 by the end of this holiday season.

Getting It Done
Replace your old strings of incandescent lights with LED strings now. In the long run, it will benefit your wallet, your sanity, and Earth.

LED lights are available everywhere this year. The cost of a string of 100-bulb LEDs can vary from $25 at the local hardware store to as low as $10 if you shop around on-line. Regardless of the price you pay, there is an initial financial investment for LEDs compared to the $4 you’ll pay for incandescents. However, you will quickly recoup your initial payout through energy savings and durability.

Here are a few places we found LED holiday lights for sale:

Environmental Lights
Christmas Lights Etc.
1000 Bulbs

And, of course, you can find strings of LED bulbs for sale at your local Home Depot or other big-box superstore.

And don’t throw away your old lights — recycle them. Many companies that sell new LEDs also recycle old, incandescent strings. The Christmas Light Recycling Program at HolidayLEDs.com is just one example.

Rules of the Challenge
The duration of this Challenge is one month, and the total CO2 reduction is 251 lbs. So, if you accept this Challenge, you’ll see about 8 pounds of CO2 reduction added to your Rally account each day for the next 30 days.

If you typically use lights for less than 30 days during the holidays, you’ll have to apply some creative math. The 251 lbs of CO2 savings in one month is based on two 100-bulb strings of lights (roughly enough lights for a Christmas tree) burning 6 hours a day for 30 days. If your lights are only up and lit for 15 days, you’ll need to replace four sets of lights to reach this Challenge’s CO2 savings value. On the other hand, if you decide to replace additional strings of lights inside or outside your house (all those trees and bushes), you can accept this Challenge again for every two strings you replace.

As with all Challenges, the most important thing is that you take a small action to reduce climate change. Don’t sweat the numbers too much; just take the Challenge!

See the Math
Let’s start with the known or estimated numbers:

• A single string of 100 old-style incandescent bulbs requires 500 watts of electricity per hour.
• A single string of 100 LED bulbs requires 50 watts of electricity per hour.
• On average, folks use two 100-bulb strings of lights on their tree
• Swapping out one string of incandescent bulbs for one string of LEDs saves 450 watts per hour. Swapping out 2 strings of bulbs saves 900 watts per hour.
• A kilowatt is equal to 1000 watts. Using 1 kilowatt for 1 hour is what your electric company describes as 1 kilowatt-hour (kWh). So swapping out 2 strings of bulbs saves 0.9 kWh for every hour the lights are lit.
• On average, lights are lit for 6 hours a day for 30 days during the holidays, or 180 hours total.
• A fossil fuel burning power plant releases an average 1.55 pounds of CO2 for every kilowatt-hour it creates.
• Each kilowatt-hour (kWh) costs about $0.12 . So, based on the assumptions above, completing this challenge will save you about $19.40 The cost of switching to new LED bulbs will be covered after about two season of use.

Now put all that together to get the following equation:

Your numbers may vary depending on the lights you use, how long they stay lit each day, and so on. The important thing is that you make some new change to an old holiday habit. Happy holidays — and Rally on!

Discussion 77 comments so far

Administrator over 3 years ago

Here's a chart from the study referenced below. GLS refers to conventional incandescent light bulbs.