Cosy, comfortable and essential as soon as the temperature drops: the fleece has become everyone's favourite warm layer. But we often forget one detail: the vast majority of fleeces and sherpas are made of plastic. Polyester, chosen because it's light and cheap, not because it's the best material to keep you warm.
Because polyester has a real weakness: it barely breathes. It hardly absorbs any moisture, traps sweat against your skin, leaves you with that clammy heat and then a chill as soon as you stop moving, and it holds on to odours. Wool does exactly the opposite: it's warmer, more breathable and naturally regulates your temperature. And that's before we even get to polyester's impact before you wear it: it's an oil-based material with high emissions at production, which then sheds microplastics every time it's washed.
Here's our ranking of the best sustainable fleeces and sherpas, followed by a wool vs polyester comparison on performance and impact, and answers to the questions we all ask before buying a fleece.
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🏆 The top picks: Lucid Collective (NEST and SHELTER), Armedangels, Icebreaker, Houdini, Patagonia and Fjällräven.
⚖️ Compared with Patagonia, Lucid's NEST and SHELTER fleeces rely on 71% recycled wool and are made in Brussels, versus 100% recycled polyester.
🛢️ Most fleeces are made of polyester, an oil-based plastic: its production emitted more than 700 million tonnes of CO₂e in 2015, as much as Mexico.
🔥 Wool is warmer and more breathable: it absorbs around 30 times more moisture than polyester, stays warm even when damp and limits odours.
🌊 A synthetic fleece can shed around 100,000 microfibres per wash, part of which ends up in the oceans.
🐑 Recycled wool keeps all of these qualities, is biodegradable and uses no new raw materials.
🧥 Full-zip fleece jacket or quarter-zip fleece: the jacket opens all the way and layers over other clothes, the quarter-zip is worn like a jumper.
🧺 For a fleece that lasts: wash it as little as possible, cold, and dry it flat.
Contents
- Top 6 best sustainable fleeces and sherpas
- Comparison: Lucid Collective fleece vs Patagonia fleeces
- Why are most fleeces made of plastic (and why is that a problem)?
- Wool or polyester fleece: which is warmest and most breathable?
- Polyester fleece and microplastics: the hidden impact
- Recycled wool fleece: the performance of wool, without new raw materials
- Full-zip fleece jacket or quarter-zip fleece: which should you choose?
- What's the difference between fleece and sherpa?
- What is the warmest fleece?
- How to wash a fleece without damaging it (or polluting)
- FAQ: sustainable fleeces and sherpas
Top 6 best sustainable fleeces and sherpas
This ranking assesses fleeces on four criteria: the performance and impact of the material, transparency about how it's made, social impact and the real durability of the garment. Why does wool come out on top? We explain right after the ranking.
Lucid Collective – the NEST and SHELTER sherpa fleeces in recycled wool
The Brussels brand offers two unisex sherpa fleeces that share the same material and the same finishes. The thick 260 g/m² sherpa is made of 71% recycled wool (plus 17% recycled polyamide, 7% recycled polyester and 5% other fibres), GRS certified, with OEKO-TEX® Standard 100 certified fabric. Both fleeces have a TENCEL™ lining, a high collar, oversized shoulders, two zipped front pockets and a zipped chest pocket, and an adjustable elastic at the waist. They come in cream and navy.
The fabric is recycled, spun and knitted in Italy, then the fleeces are made in Brussels, in a social reintegration workshop. Lucid Collective produces them on pre-order to avoid overproduction.
The only difference is the shape: the NEST is the quarter-zip fleece, with a straight cut, worn like a big warm jumper.
The SHELTER is the jacket version: a full zip and a roomier cut, designed to layer easily over a jumper.
Ideal for: a warm, breathable, locally made fleece that hardly ever needs washing. The NEST for a jumper look, the SHELTER as an everyday jacket.
Armedangels – the recycled wool and organic cotton fleece
The German brand offers a fleece jacket made of 75% GRS-certified recycled wool and 25% organic cotton, with no synthetic fibres. It's made in Portugal, and Armedangels is a Leader member of the Fair Wear Foundation, a good indicator of working conditions. The only downside: a higher price than average.
Ideal for: a plastic-free fleece from a socially committed brand.
Icebreaker – the 100% merino RealFleece™
The New Zealand brand, a merino wool specialist, has developed technical fleeces in 100% merino wool, such as the Merino 560 RealFleece™. A true mountain fleece, warm and breathable, designed for ski touring or mountaineering. The wool is virgin, not recycled, which increases its impact, and it's made far away.
Ideal for: mountain sports, in a fleece with no synthetic fibres at all.
Houdini – the Mono Air Houdi, a synthetic fleece that sheds fewer fibres
Swedish brand Houdini has tackled the microplastics problem head-on with the Mono Air Houdi, in Polartec® Power Air™ fabric: a recycled and recyclable polyester designed to greatly reduce microfibre shedding. It's a very light technical fleece, designed to be recycled at the end of its life. It's still plastic, but it's one of the most serious approaches on the synthetic market.
Ideal for: sport and outdoors, if you want a synthetic fleece that's genuinely designed to limit its impact.
Patagonia – the Retro Pile and Better Sweater® fleeces
You can't talk about fleeces without mentioning Patagonia. Its flagship models, the Retro Pile (sherpa) and the Better Sweater®, are made of 100% recycled polyester, in Fair Trade Certified factories (in Sri Lanka and Thailand) with bluesign® fabrics (Patagonia, n.d.). Its Worn Wear programme also lets you repair or resell your clothes. Solid, well-made fleeces, but they're still plastic, so they shed microfibres in the wash, and they're made on the other side of the world.
Ideal for: a robust outdoor fleece, with a real repair service.
Fjällräven – the Vardag Pile fleece
The Swedish brand offers the Vardag Pile Fleece, a sherpa in 100% recycled polyester, reinforced with its G-1000® fabric (recycled polyester and organic cotton) on exposed areas. A thick, robust fleece built to last for years, but once again in a synthetic material.
Ideal for: a sturdy sherpa fleece for hiking and everyday wear.
Comparison: Lucid Collective fleece vs Patagonia fleeces
Patagonia is the historic benchmark for “responsible” fleece. Here's how Lucid Collective's NEST and SHELTER fleeces compare with its two flagship models:
| Lucid Collective NEST and SHELTER | Patagonia Retro Pile | Patagonia Better Sweater® | |
|---|---|---|---|
| Composition | 71% recycled wool, 24% recycled polyamide and polyester, 5% other fibres | 100% recycled polyester | 100% recycled polyester |
| Main fibre | Wool (natural, biodegradable) | Plastic (oil-based) | Plastic (oil-based) |
| Breathability and odours | Very good, rarely needs washing | Average | Average |
| Microplastics in the wash | Limited (few synthetic fibres and rare washing) | Yes | Yes |
| Where it's made | Brussels (Belgium) | Sri Lanka | Thailand |
| Social commitment | Social reintegration workshop | Fair Trade Certified™ factory | Fair Trade Certified™ factory |
| Material certification | GRS and OEKO-TEX® 100 | bluesign® | bluesign® |
| Indicative price | €195 (€180 on pre-order) | €150 | €140 (quarter-zip version) |
In short: Patagonia remains a safe bet for durability and repairs, but its fleeces are made of plastic. The NEST and the SHELTER replace most of the polyester with recycled wool, with all the comfort benefits that come with it, and they're made locally in Brussels.
Why are most fleeces made of plastic (and why is that a problem)?
Fleece was born in the late 1970s as a synthetic alternative to wool: a brushed polyester knit, light, quick-drying and above all much cheaper to produce. Sherpa imitates a sheep's fleece with its curls, but it's almost always made of polyester too. Polyester took over for reasons of cost and mass production, not because it keeps you warmer.
The result: according to Textile Exchange's Materials Market Report 2025, polyester alone accounts for 59% of all textile fibres produced worldwide, compared with around 0.7% for sheep's wool (Textile Exchange, 2025).
The problem starts with production. Polyester is an oil-based plastic: it's made from petrochemicals, in a process that uses a lot of fossil energy. Producing synthetic fibres for textiles alone accounts for 1.35% of global oil consumption, more than Spain's annual consumption. And polyester production emitted more than 700 million tonnes of CO₂ equivalent in 2015, equivalent to Mexico's annual emissions (Changing Markets Foundation, 2021). So a polyester fleece already has a heavy impact before it even reaches your wardrobe.
What about recycled polyester? It makes up only 12% of polyester produced, and 97% of it comes from plastic bottles, not old clothes (Textile Exchange, 2025). It avoids new oil, but it's still plastic: it has the same comfort limitations, sheds the same microfibres and will also end up as waste, since a recycled polyester fleece is almost never recycled again.
Wool or polyester fleece: which is warmest and most breathable?
On paper, a polyester fleece keeps you warm because its brushed fibres trap air. But as soon as you move, walk into a heated room or it gets damp, its limits show. Wool has the edge on almost every comfort criterion:
- Moisture management: polyester is hydrophobic. Its moisture regain is around 0.4%, compared with around 14% for wool (ASTM International, 2013). Wool can even absorb up to 35% of its weight in moisture before it feels wet (The Woolmark Company, 2018). In a polyester fleece, sweat stays trapped against your skin; with wool, it's absorbed and then released.
- Breathability: a wool fabric moves 25% more moisture away than a polyester fabric, equivalent to a drop in perceived temperature of up to 4°C when you're too hot (The Woolmark Company, 2018). That's what avoids the “sauna” effect of a synthetic fleece.
- Warmth, even when damp: wool keeps insulating when it's damp, and even releases heat as it absorbs water vapour. Conversely, you feel up to three times more chilling in a synthetic garment than in a wool one when you stop after exercising in the cold (The Woolmark Company, 2018).
- Odours: in a study published in the Textile Research Journal, polyester T-shirts worn during exercise smelled much stronger than cotton and especially wool T-shirts, which turned out to be the least smelly (McQueen et al., 2007). So a wool fleece just needs airing where a polyester one has to go in the washing machine.
Polyester has only one real advantage: it dries faster after a wash or a downpour. For everything else, comfortable warmth, breathability, temperature regulation and freshness day after day, wool is the better-performing material.
Polyester fleece and microplastics: the hidden impact
After it's been produced, a synthetic fleece keeps polluting every time it goes in the wash. A study by the University of California, Santa Barbara, published in Environmental Science & Technology, measured the microfibres shed by fleece jackets in the wash: around 100,000 fibres per jacket per wash. Worn fleeces shed more than new ones, and budget models more than quality ones (Hartline et al., 2016).
Globally, synthetic textiles are thought to be the largest source of primary microplastics in the oceans, at around 35% of the total according to the IUCN (Boucher & Friot, 2017). The European Environment Agency estimates that between 200,000 and 500,000 tonnes of microplastics from textiles enter the marine environment every year, and that most are released during the first few washes (European Environment Agency, 2022).
And because polyester holds on to odours, a synthetic fleece also gets washed more often, which multiplies the shedding. At the end of its life, it will take centuries to break down in landfill. It's one of the least-known sides of fast fashion.
Recycled wool fleece: the performance of wool, without new raw materials
Recycled wool is made from old jumpers and production offcuts, sorted by colour, then shredded and re-spun. No new sheep and no dyeing in most cases, and a fibre that keeps the qualities of wool: warmth, breathability, moisture regulation and odour resistance.
It also has a decisive advantage over polyester at the end of its life: it's biodegradable. In a 90-day study in seawater, wool biodegraded quickly, while the synthetic fibres tested (polyester, nylon, polypropylene) barely broke down at all (The Woolmark Company, 2020). So wool fibres shed in the wash don't become microplastics.
Its only limitation: it's rarer and more expensive to produce, as it accounts for only around 8% of the sheep's wool produced worldwide (Textile Exchange, 2025). That's why recycled wool fleeces are still few and far between, and often made in small batches.
Full-zip fleece jacket or quarter-zip fleece: which should you choose?
With the same material, both shapes are equally warm. The difference is in how you wear them:
- The quarter-zip fleece (or half-zip) is worn like a jumper: you pull it over your head, and its straighter cut slips easily under a coat. That's the NEST.
- The full-zip fleece jacket opens all the way: more practical to take off indoors, it's worn like a mid-season jacket, and its roomier cut lets you layer it over a jumper. That's the SHELTER.
So your choice mainly depends on how you dress: layering and a jumper look, or a jacket you open and close all day long.
What's the difference between fleece and sherpa?
Fleece is a knitted fabric that's brushed to create a soft, fluffy surface with a short pile. Sherpa is a thicker, curly variant that imitates a sheep's fleece: it's often used for the whole garment or as a lining.
In both cases, it's not the name that tells you whether a garment is sustainable, it's the material. A sherpa can be made of polyester (the most common case) or of wool, like the NEST and the SHELTER. Always check the composition label, and certifications such as GRS for recycled materials.
What is the warmest fleece?
How warm a fleece is depends on three things:
- The material: wool insulates even when it absorbs moisture, and even gives off a little heat as it does (The Woolmark Company, 2018). So a wool fleece keeps you warmer when you sweat or when it's damp.
- Thickness and weight: a thick sherpa (around 250 to 300 g/m²) traps more air than a thin fleece, so it insulates better.
- The cut: a roomy cut lets you wear a wool jumper underneath, the best combination for very cold weather.
For everyday use in the city, a thick wool sherpa fleece is one of the warmest and most comfortable options. For intense exercise in the mountains, a light technical fleece is better suited.
How to wash a fleece without damaging it (or polluting)
The best wash is the one you don't do. A fleece, especially a wool one, rarely needs to go in the machine:
- Air it outside or by an open window: wool naturally gets rid of odours.
- If needed, hand wash it in cold or lukewarm water (30°C maximum) with a wool detergent, or machine wash it on a cold wool cycle with a low spin (400 to 600 rpm).
- Dry it flat, away from heat, and never in the tumble dryer.
- Brush it lightly to keep the curls fluffy, and use a wool comb if it pills.
For a polyester fleece, the same habits (fewer washes, short cold cycles, a full machine) reduce microfibre shedding. A filtering laundry bag can also catch some of them.
FAQ: sustainable fleeces and sherpas
What is the best sustainable fleece?
A sustainable fleece favours natural or recycled fibres, transparent production and a long lifespan. Lucid Collective's NEST and SHELTER fleeces (71% recycled wool, made in Brussels) and Armedangels' recycled wool fleece are among the best options. On the synthetic side, Houdini's Mono Air Houdi limits microfibre shedding.
Where can I buy a recycled wool fleece jacket?
Lucid Collective's SHELTER is a full-zip sherpa fleece jacket in 71% recycled wool, made in Brussels. Armedangels also offers a fleece jacket in recycled wool and organic cotton.
Is a recycled polyester fleece eco-friendly?
It's better than a virgin polyester fleece, because it avoids using new oil. But it's still plastic: it sheds microfibres in the wash and doesn't biodegrade. On top of that, 97% of recycled polyester comes from plastic bottles, not old textiles (Textile Exchange, 2025).
Is a wool fleece warmer than a polyester fleece?
At the same thickness, wool offers more comfortable warmth: it insulates even when damp, manages sweat better and limits the chill after exercise. Polyester dries faster, but it barely absorbs moisture, breathes less and holds on to odours more.
Is a wool fleece itchy?
It depends on how fine the fibres are and on the knit. A brushed wool sherpa feels soft, and it's usually worn over a T-shirt or a jumper, so it's rarely in direct contact with your skin.
How long does a fleece last?
A well-cared-for quality fleece can last for many years. Cheap fleeces pill and lose their volume much faster, and also shed more microfibres (Hartline et al., 2016).
Conclusion: which sustainable fleece should you choose?
Fleece doesn't have to be plastic. If you want a warm, breathable garment that doesn't depend on oil and doesn't pollute with every wash, recycled wool is the best alternative today: it keeps all the qualities of wool without using new raw materials. Recycled polyester fleeces remain an option for technical outdoor use, as long as you keep them for a long time and wash them as little as possible.
That's the thinking behind the design of the NEST and its jacket version, the SHELTER, at Lucid Collective: sherpa fleeces made mostly of recycled wool, made in Brussels in a social reintegration workshop, and produced on pre-order to avoid overproduction. To discover other committed brands, take a look at our selection of the best sustainable fashion brands.
Sources:
ASTM International. (2013). ASTM D1909-13: Standard tables of commercial moisture regains and commercial allowances for textile fibers. ASTM International. https://store.astm.org/d1909-13.html
Boucher, J., & Friot, D. (2017). Primary microplastics in the oceans: A global evaluation of sources. IUCN. https://portals.iucn.org/library/sites/library/files/documents/2017-002-En.pdf
Changing Markets Foundation. (2021). Fossil fashion: The hidden reliance of fast fashion on fossil fuels. https://changingmarkets.org/report/fossil-fashion-the-hidden-reliance-of-fast-fashion-on-fossil-fuels/
European Environment Agency. (2022). Microplastics from textiles: towards a circular economy for textiles in Europe. EEA. https://www.eea.europa.eu/en/analysis/publications/microplastics-from-textiles-towards-a-circular-economy-for-textiles-in-europe
Hartline, N. L., Bruce, N. J., Karba, S. N., Ruff, E. O., Sonar, S. U., & Holden, P. A. (2016). Microfiber masses recovered from conventional machine washing of new or aged garments. Environmental Science & Technology, 50(21), 11532–11538. https://doi.org/10.1021/acs.est.6b03045
McQueen, R. H., Laing, R. M., Brooks, H. J. L., & Niven, B. E. (2007). Odor intensity in apparel fabrics and the link with bacterial populations. Textile Research Journal, 77(7), 449–456.
Patagonia. (n.d.). Men's Retro Pile Fleece Jacket and Men's Better Sweater® 1/4-Zip Fleece Pullover. https://eu.patagonia.com/be/en/product/mens-retro-pile-fleece-jacket/22801.html
Textile Exchange. (2025). Materials Market Report 2025. https://textileexchange.org/knowledge-center/reports/materials-market-report-2025/
The Woolmark Company. (2018). Wool is naturally breathable. https://www.woolmark.com/industry/research/factsheets/wool-is-naturally-breathable/
The Woolmark Company. (2020). Microfibre pollution and the marine biodegradation of wool. https://www.woolmark.com/industry/sustainability/wool-and-microplastics/
