| What it is | A jacket with down or synthetic fill |
| Worn as | Mid layer or warmth at rest |
| Fill | Down or synthetic |
| Difficulty | Beginner |
An insulated jacket, or ‘puffy’, is a jacket filled with down or synthetic insulation that traps warm air to keep you warm. Worn as a mid layer or an outer layer at rest, it’s the standard way to add warmth outdoors. The key choice is down (warmest for weight) versus synthetic (warm when wet).
Down or synthetic
A down jacket is warmest for weight; a synthetic jacket stays warm when wet — see down vs synthetic.
In the system
Worn as a warm mid layer or thrown on at rests.
Frequently asked questions
What is an insulated jacket?
An insulated jacket, often called a puffy, is a jacket filled with down or synthetic insulation that traps warm air to keep you warm. It's a core piece of cold-weather and layering kit, worn as a warm mid layer or thrown on over everything during rests and at camp.
Down or synthetic insulated jacket?
Down is warmer for its weight and packs smaller, best for cold, dry conditions; synthetic keeps insulating when wet and dries faster and costs less, best for damp climates and active use. The right choice depends on your conditions — many people own one of each.
When do you wear an insulated jacket?
As a mid layer for warmth while moving in the cold, and especially as the warm layer you pull on the moment you stop — at rests, belays, summits, and camp — when your body cools quickly. It's a key defense against getting chilled outdoors.
Sources
- Insulation basics — The Mountaineers