From toxic waxes to wick trimming; why it’s not just the flame to watch when burning candles at home

There are some simple steps to reduce the danger of burning candles at home without ruining the ambience. Photo / Getty Images
When the weather is cold, the risk of house fires increases. Despite the fact that we might start ditching the heaters soon, if you’re into lighting candles, it’s probably not something you’re going to give up just because it’s getting warmer. Ashley & Co founder Jackie Ashley speaks to Lucy Slight about how to keep safety a priority when burning candles – at any time of the year.
While we certainly don’t need candles to provide a light source in this day and age (power cuts not permitting), there’s something very comforting about lighting a candle on a cold dark night.
It makes sense that when the temperature drops, there is an increased risk of house fires. AMI Insurance data shows that between summer and winter 2023, there was a nearly 40% increase in house fires.
The report showed that the most common causes of house fires, in order, are cooking, indoor fires, electrical such as overloaded multi-boards, heating sources and coming in at number five, candles.
Whether you’re lighting a candle for the scent or the ambience – or a power cut – it’s important to be vigilant about safety. It takes less than 30 seconds for a small flame to turn into a major fire, and mere minutes for smoke to fill a house.
For this reason, you want to make sure when burning a candle you keep it away from drafts and have it positioned on a flame-resistant surface.
“Drafts can disrupt the flame, leading to an uneven burn that can compromise both the candle’s performance and safety,” says Jackie Ashley, founder of New Zealand scent company Ashley & Co.
The vessel itself can pose a safety risk too, she explains, noting that there are different qualities of glass. “Borosilicate glass is known as one of the safest due to its resistance to high temperatures,” says Ashley.
When burning your candle, it is imperative that you snuff the candle out when you still have around 1cm of wax remaining at the bottom. In 2017, Australasian candle company Ecoya was put under the spotlight when an Auckland scientist reported that the glass of the candle vessel shattered while the candle was alight.
At the time, Ecoya stressed the importance of leaving a 1cm pool of wax at the bottom of the vessel to ensure the integrity of the vessel.
Ecoya’s vessels are made from annealed soda lime silicate glass, which, like borosilicate glass, is designed specially for candle burning, but even so, if a candle is left burning for too long, the vessel may become hot to touch, risking injury.
“Based on an average 300g size, a safe amount of time to burn a candle is three to four hours at a time,” says Ashley, adding that keeping burn time restricted will extend the life of your candle.
Trimming your wick before you light your candle each time also serves as a way to extend the life of your candle and increase the level of safety. If your wick is longer than half a centimetre above the wax, use a wick trimmer to slice off the top.
Candle safety instructions on Ecoya’s website explain that if the wick becomes too large, it can mushroom, causing excess soot and an increased heat, which will burn through the candle faster and decrease the overall burn time.
The type of wax and wick material can also affect the melting point of the candle, the scent throw and emissions.
“An unbleached cotton wick is ideal, as it avoids emitting harmful toxins while burning,” explains Ashley.
The safest types of wax to avoid potentially unsafe chemical emissions are soy, coconut and beeswax candles. Sustainably sourced palm oil is another safe and eco-friendly wax choice.
Many cheaper candles are made from non-toxic food-grade paraffin wax, and while they are not deemed harmful, paraffin wax has been found to release volatile organic compounds when heated, so it’s something to be aware of when purchasing candles.
“Additionally, not all fragrances are created equal, but reputable brands use those specifically adapted for safe and effective burns,” adds Ashley. “Depending on the fragrance strength, burn your candle in a well-ventilated area.”
Tui & Kahili is Ashley & Co’s most popular candle scent. The brand’s candles are made from RSPO-certified, sustainably sourced palm oil.
Ecoya’s Mandarin Gin Madison Candle is a blend of orange, mango and sweet mandarin made from 100% natural soy wax.
Neve candles are hand poured in New Zealand using 100% natural soy wax. The wicks are made from FSC certified wood.
New Zealand brand Bide launched its range of candles in 2023. They are hand poured using 100% natural soy wax with unbleached, zinc and lead-free cotton wicks.
Lucy Slight is a beauty and lifestyle columnist for the Herald. She has worked in print and digital publishing for the past 17 years in New Zealand and Australia, across several well-known fashion, beauty, entertainment, food and home titles. Recently, she’s looked into a TikTok trend that taking a magnesium supplement can help your anxiety, whether all children need to be using gentle bath products on their skin, and the skincare tradies use.