Science Questions

Are candles bad for the environment?

Sun, 18th Dec 2011

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Question

Luke, Essex asked:

My question is, is burning candle is bad for the environment? And also, is paraffin candle worse or better than wax candles?

Answer

Chris -   If you wind the clock back a few hundred years when people made candles out of pig fat – tallow, the candles would’ve been made from an animal product and the animals would’ve eaten plant matter in order to make the fat that went into their body and then became the candle.  And that's actually why rats used to love candles.  Historically, if you read old John Mansfield books and things like that, you'll see that the rats gnawing on candles because they like the fact they're made of fat. 

And because the pigs that they were made from would’ve eaten plant matter, the carbon in the candle wax would’ve come originally from the atmosphere.  Trees would’ve turned it into sugars and turned it into starches, and cellulose and things that the animals would’ve eaten and then incorporated into their own body.  So, burning those candles isn't bad for the environment because basically, it’s carbon neutral in that regard, although I suspect there's a few partially burned hydrocarbons and I suspect Dave might have a comment on that.  Modern day candles though are made from paraffin wax.  These are fairly long chains of hydrocarbons.  They're oil based, burning those, you're burning a fossil fuel, so they're not so good for the environment.

Luke -   Also, what sort of implications are they to a light bulb say, how many candles and how long do you have to burn those for to equate this with light bulbs?

Chris -   Dave, do you know the relative comparison between a candle and light bulb?

Dave -   I'm not entirely sure.  I do know that candles are very, very inefficient compared to a light bulb.  They are running very cold, they're not completely burning, you get quite a lot of soot out on top of them.  Really 95%, 99% of their energy is going into producing heat radiation and heating things up rather than actually producing a light which you actually want.

Helen -   And also, going back to the tallow point, pigs aren’t necessarily carbon neutral.  Certainly not greenhouse gas neutral, as they do produce a lot of methane and that's a very powerful greenhouse gas.  I think you might have to take that into account as well.

Chris -   True, but I guess historically, there wouldn’t have been that many of them so we probably wouldn’t have to worry too much, would we?

Dave -   The other big environmental thing which was a really major issue with candles, especially best quality ones, is that they were made from spermaceti from sperm whales.  They have a big waxy, oily area in their heads which they used to focus sound waves for their sonar.  And really, quite a lot of the best quality candles are made from those and did hideous things to whale stocks.

Chris -   I think you've got something ridiculous like 10 tonnes of oil coming from a single sperm whale weighing  between – is it 30 tons, Helen, the sperm whale?

Helen -   Absolutely, and I can't agree more that making candles out of whales is really bad idea.

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