Best Synthetic Insulated Jackets of 2025 | Fully Field Tested and Reviewed
Synthetic insulated jackets offer reliable warmth in wet weather, compressibility and a long-lifespan. Here's what to look for and the best options out there.
The best synthetic insulated jackets are those that are dependable and that will see you through the rough stuff. The first synthetic insulated jacket that I purchased did just that. It was a Mountain Equipment Fitzroy Jacket and it was one hell of a thing. Fit to burst with PrimaLoft insulation, it lived in the bottom of my climbing pack only to be pulled out during cold, wet and windy winter climbing belay stances that you so frequently find up in the Highlands.
The bombproof, heavy and warm style of the Fitzroy was the trend when I bought my first synthetic jacket – it was built to last in the ‘ming’ that you’re so often blessed with in Scotland and it did the job extremely well. To be honest, synthetic insulation was the piece of equipment you purchased because you knew you had to, not because you wanted to – oh how things have changed with recent developments in synthetic fibres.
Synthetic insulation is made from polyester that has been spun into filaments that creates a pocket of air between each fibre. This pocket then warms up from your body temperature and thus, provides warmth. This is exactly the same way natural down can be used to keep you warm.
Down versus Synthetic
We’ve not yet quite mastered a precisely like-for-like synthetic alternative to down – its formation is just too unique – and so there are still some downsides (sorry) to synthetic insulation in comparison to it. That being said, there are also some upsides to using synthetic insulation over down.
Warmth-to-Weight
Down offers the better warmth-to-weight ratio over synthetic insulation materials. Put simply, the unique 3D structure of down creates what is called loft which traps air more effectively than any synthetic fill in production at the moment. We could reach a point soon where synthetic insulation will be able to match up though. PrimaLoft is a good example of a type of fill that is getting very near to hitting that same warmth-to-weight ratio.
Some factors that make a good synthetic insulated jacket. Pictured: the Black Diamond Vision Hybrid
Wet weather performance
Down doesn’t have a natural ability to repel water (on a goose or duck it’s protected under larger, oily feathers), and so, if it gets wet it will clump together, lose its loft and in turn fail to trap warm air. Synthetic insulation on the other hand won’t collapse when it gets wet to the same extent as down, so in wet conditions you can still count on some insulation value. Bear in mind though, that these days it’s possible to treat down with a solution that gives it hydrophobic properties – so it’s hard to say outright that synthetics are better in wet weather than down! The debate rages on…
Sustainability
Plucking a helpless goose/duck of their lovely insulating down isn’t a very nice thing to do. Fortunately, many reputable outdoor brands these days (though not all of them) take measures to ensure that the down they use is responsibly sourced. This is an argument explored in our best down jackets test.
On the flip side, many are concerned about the impact of synthetic fibres on the environment – they’re normally made from plastic after all. To address this issue, brands like Polartec and PrimaLoft have managed to develop fills that can be recycled. There’s also a fully biodegradable and recycled fibre called PrimaLoft Bio which is now available in some jackets. With these developments in mind, the scale is perhaps tipping in favour of synthetics on this front.
OM Editor Will has taken a range of jackets out with him in Snowdonia and the Brecon Beacons. I took a bunch up to the Highlands and the Alps during some ski touring weekends. Many of the items featured here were actually good enough to be selected for our Green Gear Guide and Outdoor 100, meaning they passed our gear team’s rigorous selection processes.
Best Overall Synthetic Insulated Jacket: Rab Cirrus Ultra Hoody
Best Value Synthetic Insulated Jacket: Keela Talus
Best Synthetic Belay Jacket: Keela Solo
Best Breathable Synthetic Insulated Jacket: Mountain Equipment Oreus
Best Weather Resistant Insulated Jacket: Páramo Torres Smock
Jordan using the Black Diamond First Light Hoody during a 2700m hut tour.
The Mountain Equipment Rampart providing a shield to blizzard conditions.
OM Editor Will taking the Jottnar Elvar on his 100-mile walk across the Beacon Way.
Rab Cirrus Ultra Hoody
Our top pick: the best synthetic insulated jacket overall in our tests
Will testing the Rab Cirrus Ultra. Will is 5 foot 10 and is wearing a UK Medium here.
Price: £230 Weight: 548g Warmth rating: 8.5/10 Best for: alpine climbing, winter walking What we liked: excellent warmth to weight ratio, protective hood What we didn’t like: nothing
We’ve tested this extensively on trips to the Scottish Highlands and the Lake District – and just for day to day wear – and from what we’ve seen this is an excellent synthetic insulated jacket. What’s quite remarkable about this is that it’s so lofty and light that it’s really hard to believe it’s not filled with down. It also has an edge over down too, because it’s the kind of jacket that we found will continue to provide warmth even when it gets wet – that can’t be said for most down jackets.
Using it in the Scottish Highlands, we noticed it was able to repel light to medium heavy rain well. In extended rainfall it did eventually become saturated but it still provided a degree of warmth even when it was wet through. Wear this underneath a waterproof jacket and you’ve got yourself a full blown suit of armour. The hood was protective, the details are smart and the fit was spot on for us. As such, it gets our top pick in this guide.
Will wearing a size M version of the Torres Smock in the Scottish Highlands.
Price: £250 Weight: 1.6kg Warmth rating: 9/10 Best for: winter hiking or activities with long static spells What we liked: wet weather performance, built to last, protective hood What we didn’t like: heavy, bulky, not very packable
British brand Páramo has relaunched its Torres Smock and it’s back with a bang. We used this out in the Lake District and the Scottish Highlands and were impressed by its dependable performance.
The important thing to know about this is that it’s a proper winter jacket. This isn’t for wearing for the walk to the pub. It’s for those gnarly mountain days that throw everything at you. We found it capably shielded us from the wind, it saw off rainfall and it kept us nice and toasty throughout our use.
It uses Páramo’s unique wet weather system. This relies on a quick drying, water resistant fabric and Nikwax’s specially formulated hydrophobic solution, and this combination, from our experience, results in wet weather protection that’s highly breathable. This was hands down the best performer in wet conditions out of all the jackets we tested.
The main downside is that the Torres Smock is a touch heavy and not ideal for days when it’ll spend long spells in your backpack. But that doesn’t put us off this. It’s the kind of garment that can make a big difference on those days when you don’t really want to even venture out.
Our pick if you’re looking for a belay-style jacket
Will using a size M version of the Keela Solo in Glencoe, Scotland.
Price: £165 Weight: 680g Warmth rating: 8/10 Best for: winter hiking, mountaineering and belaying What we liked: very lofty and comfortable, good technical details, good value What we didn’t like: a touch on the bulky side
Just like the Talus jacket which is also in this round up, this is an item that we found to offer top notch performance to rival jackets at much higher price points. From what we saw testing this out in the Scottish Highlands in autumn, it’s super warm, very lofty and it offers good performance in damp conditions too. We also liked the technical details, including the broad, mouldable peak on its hood, the two-way main zips and Velcro cuffs. It’s essentially got all the kind of details you’d want from a belay jacket.
It’s filled with PrimaLoft Gold insulation, a fill that, from our experience, offers reliable warmth when wet and good long-term loftiness too. It’s pretty burly, so it’s not the most packable jacket in this list, but it’s not the bulkiest either.
Torn between the Talus and this? This one’s warmer and only a touch heavier while the Talus, we’d say, is a bit more slimline and more suited to slightly higher-paced activities.
Best lightweight and breathable insulator for high output use
OM editor Will (who is 5 foot 10) wearing a size M ME Oreus jacket on a campout in the Lake District.
Price: £335 Weight: 390g Warmth rating: 6.5/10 Best for: winter hiking, alpine climbing, ski touring What we liked: innovative fill, high recycled content, very light and packable What we didn’t like: fabrics are quite noisy and feel a touch thin
At just 390g this is very light and it’s also very packable, bundling up to about the size of a small loaf of bread, but it gives off a lot more warmth than you’d expect. We found it brought us the right kind of warmth levels for active use in cold conditions – activities where you’re getting your blood pumping. In our tests, we used it while hiking in the mountains of Glencoe in some chilly early winter weather and it did the job we needed it to. From what we’ve seen, it’ll serve alpine climbing and ski touring really well too.
The fill it uses has supposedly been in development by Mountain Equipment for five years. Called Aetherm, it feels a lot like PrimaLoft, but the difference is that the clusters of fibres are woven into a reflective internal layer – kind of like a very high-spec foil blanket.
It’s designed as a jacket you can throw over a waterproof shell, wear just over a baselayer or as a midlayer. We really liked it as a midlayer as it’s not too bulky or puffy to get under a jacket but it still warms well even when the fill is compressed.
The Keela Talus used on a wet day in Wales by OM tester Callum
Price: £140
Weight: 600g Warmth rating: 6/10 Best for: hiking, hillwalking, mountaineering What we liked: excellent value, durable What we didn’t like: on the heavy side
The Keela Talus is the best value insulated jacket around. Having tested it thoroughly, we’ve can vouch for this as being perfect for anyone who tends to venture into cold and wet places. It features 60gsm of PrimaLoft Gold synthetic fill, bringing lightweight warmth and insulating performance even in wet conditions. What’s more, at least 50% of this fill is made from recycled content, more specifically, plastic bottles diverted from landfills.
Then there’s the outer shell fabric which is both lightweight and durable thanks to the Cordura fibres that make up the ripstop thread within it. Stretchy fleece-lined panels then line the sides of the torso and under the arms to add a bit of extra comfort and to aid the overall temperature regulation as well.
Features include an external zipped pocket on the chest, a zipped pocket on the inside and then two handwarmer pockets which are large enough to take an OS map. There’s also elasticated cuffs, an adjustment on the hem in the form of a glove-friendly cinch and an adjustable hood. Speaking of the hood, this has a malleable wired peak to keep the rain off your face and it’ll fit comfortable underneath a climbing helmet.
Catrin using the Phoenix Stretch on an autumn hike
Weight: 470g Price: £125 Warmth rating: 5/10 Best for: casual wear, hiking, backpacking, climbing
What we liked: lightweight, good value What we didn’t like: not the warmest or most packable
The Phoenix family of well-priced synthetic insulated jackets (Icarus for men) has been around for a few years now. We’ve seen a lightly insulated version, a heftier one, now we have this new one with super stretchy side panels and a nice new Pertex Quantum Eco face fabric. For just £125, you get “active insulation” with this jacket, providing breathable warmth.
This is how it works. There’s narrow baffles and a down-like synthetic fill for warmth, but then big stretchy panels under the arms that will let some hot air escape while also giving you a nice range of movement as well. With all that in mind, it’s going to be climbers who’ll get the most out of this jacket – it’s the kind of thing you could wear on the crag during those colder climbs from early spring through to autumn. But it’ll appeal to backpackers, hikers and bikepackers too.
There are excellent eco credentials. Montane have used a bunch of recycled fabrics in this jacket. You’ve got the outer Pertex Quantum Eco which is made from a 50% recycled polyester, the inner liner which is 100% recycled and then a PrimaLoft Silver synthetic fill on the shoulders and hood that’s made from 100% recycled materials as well. As for features, there’s everything you need: a water-resistant and windproof outer, internal storm flap underneath the main zip, deep hand-warmer pockets and a snug hood which is designed to fit comfortably under a climbing helmet.
Raji wearing the Cálido during our test trip in the mountains of North Wales
Weight: £78 Price: 350g Warmth rating: 6/10 Best for: casual wear, hiking and backpacking
What we liked: good value, sustainably made, unique design What we didn’t like: not the best warmth-to-weight, hood doesn’t hold well
The Teca Cálido jacket has been built with sustainability in mind, with a shell that’s made from a repurposed polyester taffeta and a fill that’s 100% recycled polyester.
This insulating performance is helped by a snug, elastic-bound hood, hem and cuffs plus two cosy handwarmer pockets and it’s packable enough to stuff inside its own chest pocket.
This thing’s reversible too. On one side you get that funky colour-blocked design with two zipped handwarmer pockets and then on the other you get more muted navy styling, with square stitch-through baffles, a zipped chest pocket and two drop-in lower patch pockets.
Hamid out with the Nano Puff on one of our Snowdonia test trips
Price: £180 Weight: 337g
Warmth rating: 5.5/10 Best for: day-to-day wear, summer backpacking What we liked: light, packable, eco-friendly, layers well What we didn’t like: not the warmest for its weight
The new-and-improved Nano Puff jacket now uses PrimaLoft’s innovative 100% post-consumer recycled polyester insulation made with P.U.R.E. (Produced Using Reduced Emissions) technology. It’s still the same high-performance 60gm PrimaLoft Gold Eco fill used in previous iterations, but with even less impact on the environment. Specifically, this innovative process reduces carbon emissions by a whopping 70% by altering the way the synthetic fibres are bonded together.
The Nano Puff also has a 20-denier 100% recycled polyester shell and lining, while the jacket is Fair Trade Certified sewn. And of course, it comes with all the traditional benefits of synthetic insulation – it offers decent warmth for weight, it’s hard-wearing and compressible, and boasts excellent moisture resistance.
The feature set is relatively simple but practical. It includes a full zip with a soft chin guard, two zipped hand pockets and an internal zipped chest pocket. There are elastic-bound cuffs and a hem drawcord. The hoody version also includes a snug elastic-bound hood. The fit is fairly accommodating, and if you hover between sizes, we’d tend to recommend going for the smaller size. But all in all, it’s a very comfortable jacket to wear.
Will testing out the Casaval in Italy. Photo: Aaron Rolph
Price: £235 Weight: 357g Warmth rating: 5.5/10 Best for: layering on cold days, casual wear What we liked: close fitting and comfortable under most shell layers, breathable What we didn’t like: not a great warmth to weight ratio
We tested this out in a range of conditions, including on a ski touring trip in northern Italy, and it impressed us with its breathable warmth.
It uses an insulation system that The North Face calls Ventrix and the idea behind this is that it keeps you warm when you’re taking it easy and stops you from getting clammy when you exert yourself. It aims to achieve this through the use of little holes that open up when the material is stretched – say when you’re reaching up for a hold or swinging your arms while ski touring uphill.
Does it work? From our experience, yes, because it’s a jacket that always seems to feel comfortable. In chilly conditions, it’s not quite thick enough to serve as your main layer of insulation, but it’ll work well as part of a system – say, with a baselayer and shell layer over the top. It’s cut nicely too, so you can wear most shells over this without feeling too squeezed in.
It’s worth noting that, while The North Face lists this as being “made from recycled materials” it actually only uses recycled content and there are some virgin materials present.
OM tester Giles out on the blustery Scottish coastline
Price: €149 Weight: 624g Warmth rating: 6.5/10 Best for: casual wear, hiking What we liked: lofty and very durable, good value What we didn’t like: boxy shape
Another sustainable offering, this time from Netherlands-based newcomer Cortazu who first burst onto the market with a three-layer jacket made from fully recycled and recyclable materials.
This, the ‘Mid-Layer’ from Cortazu features lightweight insulation to provide a nifty balance between warmth and weight for when you’re working hard. Special props have to go out to that Airtastic outer fabric that offers a good level of stretch and a soft touch, giving it a great level of comfort when worn as either an standalone jacket for warmer climes, or part of a layering system during the cooler months.
This time Cortazu’s sustainability is focused on re-greening farming land for countries in need. For every jacket sold, Cortazu are promising to work with Justdiggit to re-green fifty square miles of what was once fertile farmland at the foot of Kilimanjaro – nothing to dislike about that.
OM editor will using the Orvis Pro on a hike up Ben Nevis in Scotland
Price: £179 Weight: 440g Warmth rating: 6.5/10 Best for: hiking, hillwalking, fishing What we liked: durable, good rain resistance, good adjustability What we didn’t like: warmth-to-weight ratio not great
This impressed us for both its lofty, cosy insulation and for its durability. OK, this is primarily made for fishing and country pursuits but we found it holds up superbly as a jacket for hiking and general outdoor activity.
The insulation in this jacket is all body-mapped: your core, arms and head are kept toasty by soft, water-resistant, 45% recycled PrimaLoft Gold Active insulation. We’re huge fans of this stuff here at Outdoors Magic; it’s light, it’s lofty, it’s super warm and it’s also brilliant at insulating even when it’s wet. Then, in the side panels and under the arms, there’s Polartec’s Alpha Insulation (another material that insulates even when wet). This is housed in a stretchy, breathable polyamide which has what feels like a light PU coating on the outside. This adds that durability to the material that we mentioned and it also forms an extra wind and moisture blocking layer.
The jacket is quite thick, so you would only really be able to get a loose and large waterproof jacket comfortably over this. On the flip side, we found that we could wear a light mid layer underneath it without thing feeling tight or restricted.
Finally, as well as two very cosy fleece-lined handwarmer pockets, there’s also a zipped chest pocket that doubles as its stuff sack.
OM testers Holly and Will with Haglofs LIM Mimic jackets on the Cumbria Way. Photos: Joe Whitmore
Price: £210
Weight: 370g Warmth rating: 5/10 Best for: hiking and backpacking, layering What we liked: light and packable, excellent warmth-to-weight, durable feel What we didn’t like: hood not adjustable
The fill Haglöfs have used here is called Mimic. It’s a mix of synthetic fibres that are designed to look like, feel like and perform like down, with the added benefit that they won’t lose their insulating properties when they get wet. These clusters are even blown into the jacket’s baffles following the same process used in down garment manufacture.
There’s more though, because these synthetic clusters also have a graphene filament mixed into them and the benefits of this are actually quite remarkable. Graphene, you see, is a material that’s mainly heralded for its remarkable low-weight, high-strength ratio, but it’s also a super conductor of heat too. That means it’ll take heat from high warmth areas, like your arm pits, and spread it throughout the jacket.
Details include deep handwarmer pockets, an elastic-rimmed hood that’s comfortable underneath a climbing helmet, elasticated cuffs and that’s about it – not much in the way of details but, as they say, Less is More (LIM).
Will testing the Rab VR Summit in Scotland. Photo: Dave Macfarlane
Price: £195 Weight: 352g
Warmth rating: 6/10 Best for: hiking, climbing, layering What we liked: good breathability, durable, well articulated What we didn’t like: nothing
This is a mid weight synthetic insulated jacket that has a lot of versatility. In our tests, we noticed it had good wind resistance, cosy warmth and also impressive breathability too, with enough permeability for hot, moist air to escape when you’re working up a sweat. It’s also amazingly light; when we weren’t wearing it, it was no inconvenience to carry in a pack.
The insulation inside it is very similar to Polartec Alpha. What we mean by that is that it’s made up of hundreds of fleecy tufts that are organised to form an insulating liner within the jacket.
After a whole winter of testing, we’ve noticed that the little bit of stretch that fabric has makes it capable of fending off abrasion. If super tough durability is paramount to you however, you might want to look for a jacket that has a higher denier rating than this one has.
Our tester Jordan using the jacket on the Cumbria Way in October
Price: $249
Weight: 473g Warmth rating: 6/10 Best for: high aerobic activities, layering What we liked: sustainably made, good articulation What we didn’t like: warmth to weight ratio isn’t great
The Outdoor Research Shadow Hoody is a synthetic insulated puffer that is sustainably crafted with recycled and bio-based materials, but also comes in muted contemporary colours and looks pretty stylish. However, when you need technical performance, it’s also cosy and packable, offering excellent warmth for weight.
The headline material here is OR’s VerticalX Eco SR insulation. This combines Repreve recycled polyester fill with Sorona, a renewable plant-based fabric that is particularly hard-wearing. The result is a highly compressible fill that offers excellent warmth for weight, a soft down-like feel and good performance even when wet.
The jacket’s hood is insulated and adjustable for an easy fit. An elastic drawcord hem and elastic cuffs with thumb loops hold things in place as you reach, stretch, and move around, whether you’re on the mountain or off it. There’s also plenty of mechanical stretch in the fabric itself. Combined with a soft feel, it makes for an exceptionally comfortable, easy-wearing jacket.
Please enter your email so we can keep you updated with news, features and the latest offers. If you are not interested you can unsubscribe at any time. We will never sell your data and you'll only get messages from us and our partners whose products and services we think you'll enjoy.
