Given that the world is falling apart, it seems odd to be talking about scented candles. Or maybe it doesn’t. As we hurtle towards Christmas, with deeper austerity and a possible no-deal Brexit on the horizon, a nice smell might be exactly what we need.

It is certainly what we want, if sales are anything to go by. Net-a-Porter has seen a 180% spike in sales since the start of the month. According to the Business of Fashion, candle sales are growing faster than the rest of the fragrance market, rising by one-third over the past two years. It seems a desire to cocoon ourselves from the outside world (olfactory, thermal or something more insidious) is higher on the agenda. Welcome to the cult of “smellness”: a small-scale form of self-care in a destabilised world.

Gucci’s Fumus candle.

Wellness and its younger sister, self-care, are crowded fields, but growing ones. According to the latest research by the Global Wellness Institute (GWI), the worldwide wellness market was worth a colossal $4.2tn (£3.3tn) in 2017, and scented candles are without doubt an extension of it. Lest we forget, consumerism is about improving things we didn’t know needed improving – such as the smell of your home.

And then, of course, there’s social media. This is the age of the bathroom selfie. The influencers who had artfully arranged flowers or a coffee table book in the background, now slot in a flickering candle.

Scented candles have a bad rap, not least because it is literally burning money. We associate them with poshness, frivolity and celebrities and anyone fluent in smellness knows it all started with Diptyque. Meghan, the Duchess of Sussex, and Victoria Beckham both burn Diptyque’s Figuier, while Beyoncé prefers Vanille. Even Theresa May likes them – blink and you would miss the Diptyque candle on the table of her now-notorious leather trouser shoot of 2016.

Gallingly, especially in the case of May, a Diptyque candle will set you back about £50 – that’s £1 an hour, if the alleged burn time of 50-60 hours holds up. That the large luxury fashion houses are now making them makes sense; the “affordable” stuff – lighters, socks and the like – tend to offer the greatest return, provide a way to court entry-level shoppers and show a commitment to self-care. Gucci’s candles cost more than £200, and the incense sticks £55.

But the candle industry of 2018 has mushroomed, and democratised. Now there are hundreds of candles, many affordable. Matthew Herman and David Kien of Boy Smells, who sell underwear and scented candles for about £20, say the idea of luxury has changed. “It’s not just about price point, it’s about how it makes you feel, and the value it adds to your life.” Zara Home, H&M and The White Company all sell candles for under £20.

So what gives? Our collective desire to burn stuff could be a hangover of hygge. This Danish concept might have tipped into parody and even danger – recent research shows that overusing candles can lead to exposure to possibly dangerous levels of fumes and an increase in house fires – but its economy burns ever brighter. The average Dane still goes through about 6kg of candle wax a year. What’s more, staying in is the new going out out, with sleepleisure – clothing focused squarely on comfort – replacing athleisure (although they are much of a muchness). Sheet-mask selfies taken in your bathroom are one of the great, weird Instagram trends of 2018, while Vogue has an entire web series showing celebrities getting ready in their loo, not their bedroom. It makes sense that the “peer in” culture would extend to a votive – and that you would want your home to smell as good as you do given that, well, you are not leaving it.

Herman and Kien agree: “People started identifying with self-care, wanting the brands they buy for their bathroom and home to be reflections of how they see themselves and their style.” While a lot of the wellness market – looking at you, yoni eggs – is pure quackery, you can’t deny the empirical power of something that smells. “I’ve turned my indoors into my outdoors,” says one friend who has been burning nature-scented candles for a decade. It is not simply that we want to look better. We want to smell better too.

If that all seems a bit glib, pay attention to the sort of smells your candles should be burning. “We all want something to make us stand out from the crowd, so adding something unusual and unexpected can really set [us] apart,” says the fragrance historian Roja Dove. Candles should “suit the function of the room”, not cross over with what we spray on our bodies.

Sophie Beresiner, the beauty director of Elle, launched her own line, No 22, in her kitchen. The most popular scent is called Laundry Room, which smells of exactly that, although Bookshelf is a close contender and has a pleasant logic to it (leather for the spine, vanilla for the sweetness of old pages, musk for the dustiness).

Bella Freud’s £45 Art candle is designed to evoke an artist’s studio (palmarosa, cedar and guiac wood are reminiscent of oil paint, old wood and paint brushes, she says). Frédéric Malle, the esteemed French nose, goes one esoteric step further to capture a time, a place and a country – “the end of a Parisian dinner when the guests have just left” – with something called Cafe Society. No dinner I’ve ever been to, mind you, but the sentiment’s there.

Dig deeper, of course, and there is probably some of that at play here. The power of smell is indisputable. Even if you are not Proust, with your memory triggered by a madeleine soaked in tea, you can appreciate the phenomenon. As a child in 1900, the philosopher Walter Benjamin needed the smell of cooked apple emanating from a bedside oven to help him sleep. For Naomi Campbell, it was 25 lily-scented candles that did the trick. “Smell is the most intimate of senses, and it is as individual as our own fingerprint, because it is totally dependent on our life experiences,” says Dove – which would figure if one of my favourites was the smell of warm sheep dung through an open window (I grew up surrounded by it).

No 22’s Laundry Room candle, £40, Net-a-Porter

The dominant scents on the market – or at least the newer, trendier ones – really are smells, rather than scents. “If it’s something you already related to, you’ll find it comforting immediately,” says Beresiner. Anya Hindmarch’s candle range is a case in point: hers smell of chewing gum, pencil shavings, washing powder, tobacco and even baby powder.

Still, Proustian power aside, that they are taking off at all is a mystery. Posher scented candles are kept in a glass cloche, which you lift to sniff the scent. (Unlit, this is referred to as its cold throw. Lit, it is called a hot throw.) How do you choose a candle online if you can’t smell it? And, let’s say people are buying them for the purposes of social media – obviously you can’t smell through social media (although frankly, give Zuckerberg time). Many candlemakers are factoring this in when they design the holders. “A candle spends 80% of its life unlit,” explains Beresiner. “I wanted to make a vessel that was as beautiful to look at unlit as it was lit.” The afterlife of her candles – their ceramic holders are primarily reused for “repotting succulents” – is almost as long as the candles themselves.

While researching this, I came across a blog suggesting women’s interest in scented candles is rooted in “equality”. “The candle scents recreate the homes they once loved, but have chosen, by their careers and lifestyles, not to create themselves,” it said. Sexism aside, there may be something in it. I live in a block of flats and my flat tends to smell of the dominant ingredient of another person’s cooking. Were I to cook more during the week, I may not need to mask the smells of those who do. I don’t have money to burn, but I will probably still burn something at the weekend.