What is the principle of keeping warm for products such as quilts and down jackets?

First of all, both of them have one thing in common, either the fiber is tight or the wool is tight, which can retain a lot of heat emitted by the body itself.

Down has the characteristics of absorbing and storing heat, so it can make people feel warm.

Cotton has the characteristic of keeping the calories as low as possible.

So I feel a little cold when I just put on a down jacket or quilt, and it will get warmer and warmer after a while.

Feather professional answer (please don't copy)