The truest sign to me that Autumn has arrived isn’t the changing of the leaves, the advent of sweater weather, or even the pumpkin spice lattes everywhere you look. The real sign of the Fall season in my life is when the seasonal sections of Target fills up with Halloween costumes, decorations, candy, and trinkets. On my recent trip to this holiday mecca, I was looking at the decorations– specifically the little lights that are meant to go into jack-o’-lanterns instead of candles– and realized the sustainability factor for these decorations has not become nearly as pervasive as it has for Christmas lights (which now commonly advertise how efficient they are on the front of the package). After a bit of research, it appeared that this topic had not garnered any real investigations. Being ever the energy-conscious consumer, I could not let that stand!

What follows is some ‘back of the envelope’ type number crunching to figure out the most efficient and green option for illuminating your carved pumpkins. Very specific data is not really available, so there are certainly some liberties taken. However just for the sake of finding ballpark answers, I’ll hope this slight lack of statistical rigor is found acceptable. But if the Senate and Natural Resources Committee is looking to tackle the issue, then this will be a good starting point.







Background

One of the main differences between Christmas lights and Halloween pumpkin lights that changes how the market approaches them is surely that Christmas lights get plugged into an outlet. Families with large Christmas light displays will see a noticeable bump in their monthly power bill, making the efficiency of these lights more present in the forefront of their minds. However, jack-o’-lanterns are instead lit up with either candles or lights that use portable, disposable batteries. Not only does this fact (and the relative smallness of pumpkin lights compared with full house Christmas lights) reduce the necessity of efficiency to most people, but it also makes efficiency calculations more difficult to come by. The power of the lights come either from the candle itself or from portable batteries, the comparison becomes fairly difficult.

But wait!

The choice of what to light your pumpkin up with is tied pretty strongly with a debate that arises every Earth Hour (an event organized where everyone turns off their lights for one full hour to symbolically support climate change and energy reduction efforts)– and that debate is whether candles, as a form of fossil fuels, actually end up emitting more carbon dioxide (CO2) than the electricity to power light bulbs do. Without jumping too deep into that issue, the point is that while candles do not require any electricity, they do release CO2 into the atmosphere (depending on the specific type of candle).

That being the case, it seems that comparing the CO2 emissions tied with various jack-o’-lantern lighting sources might be the easiest and most digestible exercise in determining the ‘greenest’ pumpkin lighting method.

Jack-O-‘Lantern Lighting Options

Real candles

Traditionally, jack-o’-lanterns were lit up exclusively by candles. The idea of candles in jack-o’-lanterns is so ingrained in people’s minds that the artificial lights often include a ‘flicker’ to mimic the actual look of candles. Because of this, the baseline lighting source is the traditional and widely-available paraffin candle. These candles are found at virtually any store that sells candles, and are created from a by-product of the refining of crude oil (hence their CO2 emissions).

As people became more environment- and health-conscious, alternative types of candles that did not emit the pollutants of traditional paraffin candles became more popular. So a second alternative are more the more eco-friendly soy or beeswax candles.

Artificial lights

(for these I’ll find a sample of flameless artificial lights that are readily available on Amazon.com and cover a variety of options for the batteries that power them)

Homemory Battery Operated Flameless LED Tea Light— These are the top selling flameless candles on Amazon. They use LED lights, replicate the flicker of a candle, and use a single CR2032 button cell battery.

bogo Flashing LED Strobe Pumpkin Lights— These lights also use LEDs, but instead they are strobe flashing lights, use multiple colors, and require two AAA batteries.

Amscan color changing pumpkin light— This light is also a color changing LED, though it has more colors, and it uses three AAA batteries.

Calculations

Again I just want to stress that what’s about to take place are rough calculations that should not be taken as 100% accurate, but rather to gain a general idea of the scale of CO2 emissions for each of these pumpkin lighting sources (wow it’s hard to try and sound scientific and serious while typing that phrase…). With that said, here’s a look at the back of the envelope on which these calculations were done:

Real Candles

Paraffin candles

For paraffin candles, considered the standard and classic candle with which to light up a jack-o’-lantern, a number of sources cite a figure of about 10 grams of CO2 released per hour of candle burn, so that is the number we will go with. For these candles, we’ll also ignore the CO2 emissions associated with the production and transportation of the candles because 1) paraffin is a by-product of various petroleum refining processes, meaning if not used then the material would go into the waste stream, 2) the low cost of the product suggests that the energy used to produce and transport them (called embodied energy) will be relatively low compared with the tangible CO2 released in burning, and 3) data for such questions is not readily available.

Paraffin candle CO2 emissions : 10 grams of CO2 per hour of candle burn

Beeswax/soy candles

On the other hand, beeswax or soy candles (the touted green alternative) are often considered carbon-neutral. This assumption is made despite the fact that they do also release CO2 when they are burned, as the released CO2 was recently absorbed by plants in the atmosphere (which was transferred by a bee to the beeswax used in those candles, or was still in the soy used for soy candles). In these instances, common practice is to not count such CO2 emissions, as they used CO2 that was in the atmosphere and will cyclically release it back, as opposed to fossil fuels (such as those in paraffin) that are releasing CO2 that had long been stored in oil reserves underground. We’ll again ignore the CO2 emissions associated with the production and transportation of the candles because 1) beeswax and soy plants are both renewable sources for material, 2) the low cost of the products suggests the embodied energy, and thus associated emissions, are relatively low (especially if these candles are bought locally, as they are commonly found at farmer’s markets and the like), and 3) we don’t have such data available.

Beeswax/soy candle CO2 emissions : 0 grams of CO2 per hour of candle burn

Artificial Lights

Each of the three artificial light options found, their equivalent CO2 emitted per hour of use will be calculated based on the batteries required to run them. Making the comparison this way will require a number of generous assumptions (back of the envelope here, don’t forget!):

The associated CO2 we’ll look at is only coming from the batteries used to power the light, not the construction or transportation of the light itself. Again, the data to find the CO2 associated with producing/transporting the light is not easy to find– but moreso, we’ll assume that the lights will be used year after year, thus minimizing how much CO2 per hour would end up being.

The California government sponsored a study on the emissions associated with producing alkaline batteries, one of the conclusions of which was that the CO2-equivalent produced for primary batteries was about 9 kilograms (kg) per kg of battery produced. This figure assumes that batteries are single use (either thrown in the trash or recycled after use) and accounts for the energy needed to store power in the batteries that will eventually add a sparkle to the eye of your jack-o’-lantern. We’ll use this number, combined with the weight of the batteries for the lights and the lifetime of that battery, to find the CO2 per hour of use associated with the lights.

Assumptions will be made on how long the batteries will last in these lights, using either the product’s page or a best guess based on battery capacity and typical drain.

Additionally, we’re assuming the use of the typical disposable batteries– any rechargeable batteries would throw off the calculation, but this analysis won’t go there.

Combine these artificial lights with the real candle options, and the final values for the five options in terms of associated CO2 released per hour of jack-o’-lantern operation is as follows:

Or in graphical form: Click to enlarge.

Very obviously, the environmentally friendly soy or beeswax candles that account for no CO2 release in their production or burning are going to come out on top here. But what might surprise you is that the options that use batteries come out significantly ahead of the typical paraffin candle. While the industrial production of the batteries to power the artificial lights (and even if you add in a fudge factor to account for the production of the artificial light itself) seems like it would obviously be energy-intensive and account for greenhouse gases, the less obvious fact of paraffin candles outdoing that by direct emissions is not as clear until you look into the numbers specifically.

Conclusion

In the end, this might come across as a silly exercise– and maybe it is, just in the name of holiday fun. Releasing 10 grams per hour with paraffin candles compared with the significant reductions possible with the other options might seem like small potatoes in the grand scheme of things– in a world where a single cow can release up to 200 grams of methane (a greenhouse gas that contributes more strongly to climate change per gram of it released than CO2) through flatulence and belches, why even question the CO2 released due to halloween decorations?

I would agree that’s a fair point, but let’s keep the calculations going really quickly. In the United States, there are about 73 million children under the age of 18. Let’s just say that half of those kids have a jack-o’-lantern (some families might not celebrate Halloween with jack-o’-lanterns, some families might not see the need for one for each child, but on the other hand many adults such as myself might still find joy in carving and lighting up pumpkins– so 50% will be our randomly chosen number. Back of the envelope!). And let’s say that for the two weeks leading up to Halloween, those jack-o’-lanterns are lit up for 3 hours per night. All of a sudden, we’re dealing with 1,533 million total hours of jack-o’-lanterns being burnt. If all of those jack-o’-lanterns are releasing 10 grams of CO2 per hour with paraffin candles, all of a sudden that’s 15,330 metric tons of CO2– or the equivalent of the annual CO2 released in a year by over 3,000 cars.

The point of all of this to show how much of a difference small changes can make. Are you an environmental criminal for lighting your pumpkin up with a paraffin candle? Certainly not. But you can be an environmental warrior by noting all these small choices that surround you (during the holidays and in your everyday life). And if you want to add some more energy-efficient related fun to your jack-o’-lanterns, check out these stencils from the Department of Energy!







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If this article on Halloween and energy use/CO2 emissions appeals to you, check out my other holiday themed articles for Thanksgiving, Christmas/Hanukkah/Kwanzaa, St. Patrick’s Day, and New Years Eve.

Sources and additional reading

Earth Hour 2013: Does it really save energy? The Christian Science Monitor

Green wax: New Scientist

Life Cycle: Burn, Baby, Burn (The Eco Impact of Candles): Huffington Post

Pumpkin Lights without a Flame: Your Energy Partners

Single-Use Alkaline Battery Case Study: CalRecycle

Versus Candles: Green Lifestyle

What’s the most energy-efficient kind of light? Grist

What’s the real environmental impact of a candle? Prosperity Candle

About the author: Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more. For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.