It’s not that I can’t afford a down jacket, but are military coats really more cost-effective?

Winter is here, and the temperature drops sharply. Down jackets are getting more and more expensive, which seems to be a topic that will not be absent every winter. When netizens are hotly discussing whether "a thousand-yuan domestic down jacket is worth the money", some college students choose a different way to keep warm - returning to traditional military coats and flowered cotton jackets. It is true that "it's not that down jackets are unaffordable, but that the alternatives are more cost-effective"!

The video of several college students walking into the classroom in military coats received millions of likes

Can military coats and cotton-padded jackets replace down jackets?

Can military coats and cotton-padded jackets truly replace down jackets as a way to keep warm in winter?

Are military coats more cost-effective? (Source: Weibo screenshot)

Whether it is a military coat, a cotton-padded jacket or a down jacket, their warmth-keeping effect is attributed to air. Air, as an excellent thermal insulation material, has extremely low thermal conductivity. Because the air molecules are far apart, there are fewer collisions and heat energy exchanges between them, making it difficult for heat to be directly transferred through these microscopic particles. Traditional military coats or cotton-padded jackets usually use a large amount of cotton or polyester staple fibers as fillers. These fillers form countless tiny still air layers inside the clothing, which can effectively block the loss of human body heat to the cold environment outside and provide a warming effect.

The filling material of down jackets is usually duck or goose down. The down in the down is in a three-dimensional flower shape, which can keep itself light and fluffy. After being filled into the down jacket fabric, it can fix more still air with a lighter weight and provide a more excellent warmth effect.

The warmth of military coats and down jackets is all due to air (Image source: generated by the author using AI)

In addition, it is worth noting that due to the good hygroscopicity of cotton fibers, cotton-padded jackets will absorb moisture from the environment in humid environments, causing the cotton layer to compact and its thermal insulation performance to be greatly reduced. Duck down and goose down are naturally hydrophobic and can maintain a relatively high dry and fluffy state in the same humidity environment, providing better thermal insulation. In general, although traditional military coats and cotton-padded jackets have a certain effect in keeping warm, down jackets have more obvious advantages in lightness, warmth and adaptability to wet and cold environments. Therefore, although traditional clothing can provide good warmth in some cases, down jackets are still a more ideal choice in severe winters.

Why can’t chicken feathers be made into down jackets?

We often struggle with the choice between duck down and goose down when buying down jackets, but there is a question: why do we rarely hear about chicken down being used in down jackets? Chickens are land birds, native to tropical and subtropical regions, where the climate is relatively warm. In the process of chicken evolution, they naturally produce less down feathers to adapt to their living environment. Therefore, the output of chicken down is small, the structure of chicken down is very thin, it cannot form down clusters, the fluffiness is poor, and it is difficult to lock a large amount of still air, so the warmth retention is poor; and the handle of chicken down is relatively prominent, if used as a filler, it may pierce the fabric, so chicken down is not used as a filler for down jackets.

Different feathers (Source: Generated by the author using AI)

Waterfowl such as ducks and geese retain more down feathers (Source: Generated by the author using AI)

Chickens naturally evolved to have fewer down feathers (Image source: Generated by the author using AI)

There are indeed cases of using crushed chicken feathers to impersonate duck and goose down in the market, but these fine feathers are far less capable of capturing air than intact down feathers and can easily pass through the outer layer of down jackets. Although chicken feathers are not suitable for making down jackets, they have important uses in other fields such as organic fertilizers and feather dusters.

How to choose a down jacket

Three things you need to know

When buying down jackets in winter, it is important to understand the following three key indicators, which will directly affect the warmth retention and comfort of the down jacket.

Three key indicators for selecting down jackets (Source: generated by the author using AI)

1. Filling weight:

Also known as the filling amount, this is an important indicator to measure the thermal insulation performance of down jackets. Filling weight refers to the net weight of pure down inside a down jacket. For example, a sleeping bag marked as 400 grams of goose down and a sleeping bag marked as 1100 grams of duck down, these numbers represent the actual weight of the down, not the weight of the entire sleeping bag.

2. Fluff content:

Refers to the down content in down that plays a significant role in keeping warm. The higher the down content, the better the warmth retention. The national standard "Down Clothing" GB/T14272-2021 stipulates that the "down content" value of down jackets should not be less than 50%.

3. Fluffiness:

The bulkiness refers to the volume occupied by a certain weight of down under certain conditions. The higher the bulkiness, the better the warmth retention of the down. Generally, the bulkiness of duck down is about 450, while the bulkiness of goose down is between 450 and 600. With this key knowledge, you can make smarter decisions when buying down jackets and find the ideal choice for both comfort and warmth.

This article is a work of Science Popularization China-Starry Sky Project

Produced by: Science Popularization Department of China Association for Science and Technology

Producer｜China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.

Author: denovo science team

Audit丨Song Lidan China Textile Construction Planning Institute