Since the beginning of human kind, people have used natural fibers like wool, furs, leathers, and down to stay warm. But, like everything else that has happened in the last two centuries, technology has a way of changing the way we live, including the way we dress.

Because of technology and innovation, we now have synthetic fibers to keep us warm. Not only common in our everyday cloths, they are becoming more and more popular in the outerwear fashion. Whether they are better, warmer or lighter are some of the questions commonly considered when purchasing outerwear.

Coats or jackets made with synthetic fibers are (for the most part) lighter than down-filled coats. In addition, there are no allergic issues with synthetic fibers, whereas a small percentage of the population is allergic to down-filled coats and cannot wear them.

The other advantage of coats made with synthetic fibers is that they are consistent throughout the entire fabric. There’s no area of the fabric that is thicker or more condense than another area on that material. The synthetic fabric is always uniform and constant; the properties/features
of the textile are always the same. This is important for warmth. Because of this feature, designers can create coats or jackets with fewer seams on them. Seams on a coat let the air pass through; therefore, the fewer the seams, the warmer the coat (of course, this depends on the style).

With down-filled coats, you have to make small pockets to keep the down together, or else the feathers or down will eventually move downwards because of gravity. Think of your duvet. The small pockets or boxes on it keep the feathers distributed as evenly as possible. It’s basically the same principle with down-filled coats or jackets.

However, there are a few drawbacks with synthetic fibers, including environmental concerns as synthetic fiber is a petroleum by-product. They are not biodegradable such as leathers, wools or downs.

Furthermore, because synthetic fibers are uniform, there's no originality to the fabric. Every fabric that gets put out is identical, whereas furs and leathers are made of unique pieces that give the coat or jacket character.

In conclusion, it's really a matter of personal choice. Those looking for something light can find that coats made out of synthetic fibers are a good choice. However, if originality is your thing and you prefer fabrics that are more in tune with nature, then down-filled jackets or other natural fibers are something to look at more closely.