How much ‘tech’ is in Uniqlo HeatTech? | Uniqlo

Having spent years living in old apartments with poor heating and poor insulation, I spent all winter with thermal underwear stuck to my skin.

The basics I wore mostly belonged to Uniqlo’s HeatTech line: inexpensive tops, leggings, and socks that have become staples for cold-weather urbanites. According to Uniqlo, the products – standard “Extra Warm” and “Ultra Warm” varieties – use “cutting technology” to “wick away moisture from the human body and convert the energy of movement into heat.” In fact, Uniqlo doesn’t call it a HeatTech base layer. He’s collaborated with designers like Alexander Wang and JW Anderson on the special edition at Heathtech, and says the products are so hot that they make “many clothes… a thing of the past.” One of their ad campaigns shows a man walking in 3C (37F) in downtown New York in a simple blazer and T-shirt.

With cooler temperatures on top of new fuel costs, it’s heattech season again. At Uniqlo stores from Manhattan to Tokyo, the items are already flying off the shelves (they usually disappear by the end of October). Demand is particularly high this year, with some Brits resorting to stocking up on thermal underwear, prompting savers worried about energy bills to invest in basic layers.

In the year Since its launch in 2003, Uniqlo has sold more than 1 billion pieces of hi-tech, boasting that the fabric used in these items “stretches 700,000 km, or 17.5 times around the world.” Uniqlo sold heattech from airport vending machines.

But how much of HeatTech’s technology is actually tech, and how much is marketing spin on good old-fashioned heaters and centuries-old knowledge of staying warm?

To learn how base layers should work, I spoke to Drew Hansen, a 40-year-old outdoor expert and gear reviewer who became obsessed with cold-weather survival after experiencing hypothermia as a teenage hiker. Normally, base layers have a limited function in a three-layer system. “A base layer isn’t designed to keep you warm; it’s designed to stop you from cooling. That sounds similar, but it’s not.”

Base layer work, says Hansen, is “primarily crooked; “to draw sweat away from your skin and into the environment”, so that moisture does not reduce your body temperature.

What really keeps you warm is insulation: Wear a separate layer over your base layer to prevent the hot air generated by your body from escaping. The third layer, called the outer layer, protects you from the elements. Here’s where the high-tech features really make a difference: The best outer layers are made with “breathable” fabrics like Gore-Tex, which keep wind and rain out while keeping your sweat out.

Cheaper base layer materials can be surprisingly effective, but it’s important to choose the right one, Hansen said. Cotton makes a poor base layer: while it holds air – good for insulation – it absorbs water and dries slowly, forcing your body to give up more heat to evaporate the water. That’s why cold air travelers have the saying, “Cotton kills.”

Instead, outdoor enthusiasts swear by synthetic materials like polyester that have tiny channels that “wick” moisture from your skin to the surface of the fabric. Others are firm believers in wool, which naturally absorbs moisture into its fibers and evaporates: “You can’t feel it on your skin,” says Hansen.

New base layer products with big R&D budgets hope they’ll wick away sweat. And blocking you. There’s a lot of hype in hiking circles around Smartwool, the brand’s signature “Intraknit” blend of soft merino wool and polyester. “Everything starts next to the skin,” says Sue Jesch, the company’s design director. “You might be wearing a trash bag over your chosen base layer, but you’re not going to be very comfortable if you don’t have something next to your skin to help maintain your microclimate or thermoregulation.”

Uniqlo’s HeatTech uses an inexpensive universal compound that tries to wick away sweat while providing protection. Each HeatTech item is made from moisture-wicking polyester, blended with micro-acrylic fibers and rayon (a material made from cellulose from trees) and sheds at one-tenth the width of a human hair. According to HeatTech’s product page, “11-micron fibers capture the energy of water particles released from the body at the nanoscale and convert it into heat. In addition, “H2O molecules move quickly between the skin and the heat-tech fabric” which “creates energy that can be converted into heat energy”. (A Uniqlo rep didn’t provide any further details on how exactly this process works, Hansen said he takes the claim “with a grain of salt.”)

Contrary to the common wisdom of layering, you can wear Uniqlo HeatTech as an item on its own. According to a representative of Uniqlo who responded by email, Hettech was founded in 2010. That led to the launch of the thickest and heaviest heattech in 2016, the so-called “Ultra Warm” level, which “provides 2.25 times the warmth of standard heattech… an example of a new ribbon heattech top that can be layered or “self-fitting.”

Hanson says that HeatTech’s promise to do all of this can hold true for casual wearers trying to stay warm at home.

“In theory – because synthetic materials absorb well – you can make them thicker to add some protective properties. And even sitting in your office you get a little wicking and protection, because even if you take off your socks at the end of the day, your feet are always moist.”

But for more strenuous outdoor use, something like Heattec can hold more moisture, because it’s a denser material. And it doesn’t actually keep you warm because, again, you’re retaining that moisture. It is a separate cover that should take this responsibility. “

I decided to try HeatTech myself. Over the weekend, I went for a long walk in the wonderful fall weather. For about half of the trip I wore a traditional set of layers: a polyester undershirt and a cotton button-down undershirt. For the second half, I wore a single Uniqlo HeatTech long-sleeved top.

The difference was striking. Both outfits kept me equally warm. But I felt dry and breezy with the layered clothing on, whereas the Heattech felt stuffy, and it made my armpit area feel numb. I was relieved when HeatTech came out; I could wear the other outfit all day.

The experience seemed to confirm what Hanson told me: Even for hardcore users, getting the right base layer is less about technology and more about understanding the principles of good old-fashioned warmth.

“When you’re looking at companies, you want the ones that speak real words, not these buzzwords that don’t have a lot of science behind them.

“You look at hunters off the coast of Greenland or Alaska, they’ve jumped ahead of all this and they’ve been the limit. This stuff has been tried and true for hundreds if not thousands of years,” said Hansen. In the year In 1995, a group of Canadian researchers compared modern military and travel clothing to a traditional Inuit clothing system made from two carabou skins, and found that the caribou clothing made the wearers significantly hotter (although the researchers noted that many of the testers were unaccustomed to the soft smell of the animal’s fur).

Hansen says one of his favorite hacks to stay warm is something that doesn’t require any special technology: changing your socks several times a day.

“Your feet produce more moisture than anywhere else on your body,” he says. Because most people wear cotton socks, the socks tend to trap moisture – which causes you to lose heat. But even travelers who use wool socks change them twice a day and definitely before bed.