| Insulation | Synthetic fibers (e.g. PrimaLoft) |
| Strengths | Warm when wet, fast-drying, cheaper |
| Weakness | Heavier & bulkier than down |
| Best for | Damp climates, active use |
A synthetic jacket is insulated with man-made fibers that mimic down, offering reliable warmth that — crucially — keeps insulating even when wet and dries fast. Synthetics are cheaper and more weather-tolerant than down but heavier and bulkier for the same warmth, making them ideal for damp climates and active use.
Why choose it
Synthetic insulation like PrimaLoft stays warm when wet — its big edge over a down jacket. See down vs synthetic.
Frequently asked questions
Synthetic vs down jacket — which should I choose?
Choose synthetic for wet or humid climates and high-output activity where it might get damp, since it stays warm when wet and dries fast (and costs less). Choose down for cold, dry conditions and when minimizing weight and pack size matters most.
Does synthetic insulation work when wet?
Yes — that's its key advantage over down. Synthetic fibers don't absorb much water and retain most of their loft and warmth when damp, then dry quickly. This makes synthetic jackets dependable in rain, snow, and sweaty, high-output use.
What is PrimaLoft?
PrimaLoft is a leading brand of synthetic insulation made of fine microfibers engineered to mimic down's warmth and softness while resisting moisture. It's one of several synthetic insulations (others include Polartec Alpha and generic polyester fills) used in jackets and sleeping bags.
Sources
- Insulation basics — The Mountaineers