You can identify it in the following steps:

1. Check the appearance:

1. The down jacket looks relatively fluffy, and every part seems to have air inside. Like full.

2. The cotton jacket looks thick, but it is not fluffy and does not feel like it is full of air.

2. Compression volume:

1. After compression, the volume of the down jacket will be much smaller than before because the fluffy air is discharged.

2. The volume of cotton clothing after compression is similar to that before, and there will not be much change.

3. Weight:

1. Although the down jacket is large, it feels very light when worn.

2. Cotton jackets are heavier than down jackets, and they are also heavier when worn on the body.

Relatively speaking, down jackets are more comfortable and warm than cotton jackets.

Extended information:

The most common fillings in down jackets are goose down and duck down. These two types are divided into white velvet and gray velvet according to color. In terms of price, the down jackets on the market are sorted as follows: white goose down > gray goose down > white duck down > gray duck down.

It may be affected by the ranking of selling prices. Therefore, many people think that these velvets are also ranked in this way in terms of quality. In fact, this is not the case. Through theoretical research and practical experience on down, generally speaking, goose down of the same quality and down content has better warmth and fluffiness than duck down, but the color has little to do with the quality of down jackets.

Baidu Encyclopedia - Cotton Clothes

Baidu Encyclopedia - Down Jackets