Fleece was introduced as Polartec in 1979, according to Advnture’s comparison of fleece and wool, and it still sits beside wool, down and synthetic fill as one of the four fabric families that keep most winter wardrobes warm. Each one solves a different problem, which is why the best answer is rarely a single fabric.
This guide explains what each winter fabric does, where it struggles and which job to give it. It is the fabric chapter of our series that begins with the winter clothes for women guide, and it pairs with the direct comparison in wool vs fleece vs down.
The Quick Reference Table
| Fabric | Best job | Main strength | Main weakness | Source |
|---|---|---|---|---|
| Merino wool | Base or mid layer | Soft; resists odour; does not chill you when it holds moisture | Feels less dry than synthetics; slower to dry; moderately durable | REI base layers |
| Synthetic (polyester, nylon) | Base layer | Excellent wicking; most durable | Some hold odour | REI base layers |
| Silk | Base layer for low effort | Very soft and slim under clothes | Moderate wicking; not durable; wash after each wear | REI base layers |
| Fleece | Mid layer | Stays warm when damp; dries quickly | Wind passes through | REI layering |
| Down | Mid or outer layer | Warmest for its weight | Loses insulation when wet; slow to dry | REI layering and down guide |
| Synthetic insulation | Mid or outer layer | Keeps insulating when damp; dries quickly; cheaper | Heavier and bulkier than down | REI down guide |
| Cotton | Warm-weather only | Comfortable and familiar | Soaks up water and chills in winter | REI layering |
Every claim in the table comes from the REI guides listed in the last column. Nothing in it is a lab test of our own.
What Does Wool Do Best?
Wool is a natural fibre that traps air and handles moisture well. REI describes merino as soft with ultrafine fibres, and says it does not chill you when moisture stays in its core and resists odour-causing bacteria. The trade-off is that merino feels less dry than synthetics and takes longer to dry, and REI rates its durability as moderate. In our view, coarser wool in coats and heavy knits can itch against bare skin, so we would keep it as a middle or outer fabric. See how it works in a coat in our winter coats buying guide.
What Is Fleece Good For?
Fleece is a polyester fabric made to be light and quick-drying. REI says it stays warm when damp, dries quickly and is a common mid layer, though wind blows through it. That makes it a smart layer under a coat or shell and a poor stand-alone choice on a windy street. Advnture’s comparison says there is no clear winner between fleece and wool, which is fair: the winner depends on your day.
How Should You Read Down and Fill Power?
REI defines fill power as the number of cubic inches filled by one ounce of down. Higher numbers mean more loft and more trapped air for the weight. In its insulated jacket guide, REI says fill power ranges from about 450 to 900 and gives a 650-fill jacket as costing about half as much as loftier options. In the down guide it adds that duck down generally tops out at 750 or 800, while premium goose down can reach 900 or more.
Down does have a weakness. It clumps and loses loft when wet and takes a long time to dry. For damp climates, synthetic fill is the safer pick, even though REI notes it is heavier and bulkier. Blends sit in between.
What About Thermal Wear?
Thermal is a use, not a fabric. It usually means a close-fitting base layer in merino, synthetic or silk. REI says lightweight bases suit moderate to cool temperatures, midweight suits cold and heavyweight suits below freezing, and that the fit should be snug so the fabric touches your skin and can move sweat. Skip loose thermals if warmth is the goal. For daily office wear, a thin synthetic or merino base is easy to hide under a shirt.
Which Fabric Suits Which Situation?
| Situation | Our suggestion | Why |
|---|---|---|
| Long cold commute, mostly dry | Merino base, wool knit, wool coat | Odour resistance and steady warmth |
| Wet, windy city days | Synthetic base, fleece, shell or synthetic puffer | Keeps working when damp |
| Dry, very cold days | Midweight base, knit, down jacket | Best warmth for weight |
| Office day with a cold walk | Thin silk or synthetic base, blouse, blazer, coat | Slim under clothes |
| Sensitive skin | Soft merino or silk against skin, wool further out | Reduces itch |
The suggestions are ours and are built on REI’s fabric notes. Skin feel varies person to person, so test any new knit on your wrist or neck before committing.
Care matters too. REI recommends detergent-free cleaner for down jackets, low-heat drying with clean tennis balls to break up clumps and hanging storage rather than compression. Read the label on every piece and follow it. For more on putting these fabrics together, see how to layer winter clothes without looking bulky.
How Do You Test a Fabric Before You Commit?
Read the label, then touch the fabric against your neck or wrist. If it itches, it will probably bother you all day. Stretch a small area gently and watch whether it springs back, and check the seams for loose threads.
For jackets, shake the garment and look at how the fill moves, and check whether it sits evenly. If you are buying online, use the routine in how to buy winter clothes online without size regret. These checks are our habits, not tests from the sources, but they take two minutes and catch common problems. For wardrobe planning, see the winter wardrobe checklist, and for style, the guide to layering outfits for cold weather.
