How to Choose a Synthetic JacketSynthetic insulation can be found in technical mid-layers, stand-alone jackets, and puffy parkas. Unlike down fill, synthetic insulation will insulate even when wet. It's also less expensive. For hanging out on belay or cruising town in the cold all you need is warmth. If you're skiing, backpacking, or climbing, weight and fit become more important in choosing an insulated jacket.
A jacket with relatively little insulation makes an excellent choice as a versatile mid-layer when you're on the move or as a primary layer when you're just hanging out by the campfire. Opt for a jacket with more insulation if you're standing around while belaying an ice climb, or you know you'll encounter brutally cold weather.
A Guide to Jacket Insulation
Most synthetic-insulated jackets use a lightweight or medium-weight nylon shell with a water-resistant DWR coating. However, a puffy with fully waterproof fabric can reduce the number of jackets you need if you think you'll encounter wet weather.
Waterproof Technologies & Materials