What is Synthetic Down? Is it Any Good?

This guide explains what synthetic down is and why you might use it vs. natural down for insulation. You will learn how synthetic down is made, the different types of synthetic down, and the products they are used in.

What is Synthetic Down?

Synthetic down is a man-made insulation made to mimic the qualities of natural Goose or Duck down. It is typically made from polyester fibers that undergo a process called melt spinning, but more on that further down. Synthetic down is ideal for outdoor gear like sleeping bags and jackets that benefit from having a high loft for maximum warmth and low weight and pack size.

Why is it called synthetic down? Natural down has such an unbeatable reputation in regard to jacket and sleeping bag insulation that a clever marketing team decided to call their new insulation material synthetic down. That isn’t the whole story, though, and the synthetic down insulation used today replicates the structure of feathers very closely.

Is Synthetic Down as Warm as Real Down?

In terms of warmth-to-weight ratio, synthetic down is not as effective as natural down. Natural down is warmer and lighter than synthetic down. Even at the low fill power of 650+ FP, synthetic down is still not as warm.

There are some other factors to consider, though. Like if the insulation gets wet or if the down has been hydrophobically treated. To fully get your head around this, you have to take certain variables into account…

First, I will start by saying there are multiple companies creating products that they may classify as synthetic down. Patagonia has its own PlumaFill insulation. Arcteryx uses Coreloft insulation, many brands use Primaloft, and there are many others out there as well as many others being developed right now.

The only time synthetic down is warmer than natural down is if they both get wet. Natural down will lose a significant amount of loft (up to 90%) and insulation value when wet whereas synthetic down is hardly even affected.