The "sandwich dressing method" has become popular! When the temperature is "hovering" at freezing point, wear this way to keep warm →

In this cold season, how should we dress to keep warm? In the past, people said that wrapping ourselves up like a "dumpling" would keep us warm. Recently, a "sandwich dressing method" has become popular among young people and has become a hot search topic among them.

So, what is the "sandwich dressing method"? Is there any scientific basis for this dressing method?

PART 01 Will the more you wear, the warmer you will be ?

The so-called "sandwich dressing method" refers to wearing clothes by imitating the multi-layered structure of a sandwich.

The key point is to choose moisture-absorbing and breathable materials for the inner layer close to the skin, such as close-fitting thermal underwear, quick-drying clothes, yoga clothes, etc.; the middle layer can wear clothes with good thermal insulation performance such as polar fleece, fleece, thin cashmere, down vests, etc.; and the outer protective layer, whose main function is to resist the cold air, wind and rain from the outside, is suitable for choosing coats with a harder texture or professional outdoor equipment, such as down jackets, cotton jackets, and assault jackets.

In the opinion of Gu Bingfei, member of the Party Committee of the School of Fashion at Zhejiang Sci-Tech University, director of the Department of Fashion Design and Engineering, associate professor, and master's supervisor, "sandwich dressing method" is this year's hot word, but the basic logic is similar to the "26℃ dressing method" and "onion dressing method" advocated in previous years.

Sweaters on sale at a clothing market in Hangzhou. Photo by reporter Huang Huixian

26℃ is recognized as the most comfortable temperature for the human body, so the principle of the "26℃ dressing rule" is: local temperature + clothing temperature ≈ 26℃; the core idea of ​​the onion dressing method is to wear layers from inside to outside and from thick to thin according to changes in temperature, so as to add or remove clothes as needed.

The reporter found that when talking about warm clothing, "air layer" is a frequently mentioned word.

Gu Bingfei explained that no matter what kind of clothing, it is impossible to fit the body completely. Therefore, the space formed between the human body and the clothing is the air layer. As the human body continues to dissipate heat, the air will slowly heat up, and at this time the air will play the role of a warm layer.

We can imagine the human body as a cylinder. The more pieces of clothing we wear, the more new gaps will appear between each piece, and the new gaps can accommodate air - eventually creating a very thick air layer.

When you wear too many clothes and the air layer is too thick, there will be a significant temperature difference from the inside to the outside, which will cause the air flow to produce "thermal convection". Once "thermal convection" occurs, the heat loss will be faster.

In addition to the "heat convection" caused by temperature differences, too many layers will also thin the air layer.

Especially when walking outdoors, clothes will rub and squeeze against each other as the body moves, which will accelerate the flow of air layers between clothes and speed up heat loss.

It can be seen from this that "the more you wear, the warmer you are" is a misunderstanding.

In Gu Bingfei's opinion, the key to keeping warm is to have a certain thickness and form a sufficient air layer. At the same time, for clothes that are close to the skin, try to choose materials that feel warm and comfortable to touch. The "sandwich dressing method" uses polar fleece, fleece and other clothes as middle-layer clothes for this reason.

"As for underwear, soft, pure cotton, or underwear with wool components generally have better moisture absorption and perspiration functions. After the human body sweats, it can effectively prevent moisture from accumulating in the clothing, affecting the fluffiness of the outer layer and reducing the thermal insulation performance." Gu Bingfei said that the fleece underwear that was popular in the past lacks moisture absorption effect. It looks thick when worn, but its thermal insulation performance is not necessarily better than the thinner pure cotton underwear that is popular nowadays.

PART 02 How to choose a down jacket scientifically ?

As the temperature drops, down items are often favored for their excellent warmth-keeping properties.

The teacher and student team of Zhejiang Sci-Tech University's Fashion Design and Engineering major conducts fashion trend analysis for the Hangzhou Sijiqing clothing market every year, and this winter is no exception.

According to the teachers and students of Zhejiang Sci-Tech University's Fashion Design and Engineering Department, down jacket fabrics this season are more suitable for wearing, lighter and softer, and better looking, bringing more added value to down fabrics. "This year, down fabrics with skin-touch feel have become a new favorite. Their soft and delicate touch is as comfortable as a second layer of skin. Practical tear-resistant nylon and ultra-thin high-density taffeta have become down fabrics that combine a sense of security and warmth."

Goose down jackets are very popular this year. Photo by reporter Huang Huixian

This winter, people's pursuit of the touch of clothing has been further strengthened.

"Plush fabrics are becoming more and more elegant, further promoting elegant comfort and sophisticated style. This season, designers use brushed, flannel and felt techniques to inject a different touch into the fabrics, which in turn enhances the soft, wrapping feel of down and cotton jackets," said the team leader.

So, when we buy down jackets, how do we choose down jackets scientifically?

Ms. Xie has been running a down quilt business in Pinghu, Jiaxing for 10 years and has developed a keen eye for selecting down jackets and down quilts.

"First, check whether the down jacket has all three labels: washing label, ingredient label, and brand label. Secondly, check the down content of the clothes. The higher the content, the better, and the maximum is 95%. The current implementation standard for down jackets is the new national standard GB/T 14272-2021." Ms. Xie said that for high-quality down quilts, the filling material is generally goose down with a 95% down content. This is mainly because duck down has inferior thermal insulation performance to goose down and has a stronger odor, and it is easy to leave a duck smell on the body after covering it for a long time.

This winter, facing the sweeping cold air, are you ready for your cold-resistant "equipment"?