From winter climbing to hiking, skiing, and everyday cold-weather use, we’ve found the best synthetic insulated jackets for every activity.
Synthetic insulation avoids the main weakness of down by remaining functional when wet. The trade-offs are less thermal efficiency and compressibility as well as more weight. These differences are becoming marginal as insulation technology marches forward at astonishing speed.
The synthetic midlayer category stresses thermal efficiency for lower-output activities. Active insulation offers more breathability for active stop-and-go pursuits. Both divisions must be able to fit under a shell.
We tested jackets while climbing, hiking, and running errands around town. And we evaluated each jacket on fit, comfort, and durability. Breathability, pack size, and overall value were also important considerations.
We’ve broken the article into three main categories:
- Best Synthetic Insulated Jackets
- The Best Active Insulation
- A Buyer’s Guide: How to Choose a Synthetic Jacket
And while there isn’t a single jacket for everyone, we’ve highlighted useful features to help you find the best jacket for your needs.
Best Synthetic Insulated Jackets of 2020
The Arc’teryx Atom AR has been in my alpine and higher-elevation rock climbing kit for years and has proven to be a reliable synthetic middle and outer layer. When the winter mountain forecast is just short of arctic, the one-pound (verified, men’s medium) Atom AR goes into the pack. And, surprisingly for Arc’teryx, the pricing is competitive.
The fit is comfortably close, which made it layer well under shells while still allowing layers underneath. The articulated sleeves, underarm gussets, and elastic-paneled cuffs kept my wrists covered in all positions. But the torso length is on the shorter side, which made the lower hem rise above my waist during reaches overhead.
The cuff dimensions are on the smaller side, which sealed my tiny wrists well, with just enough stretch to be pushed a few inches up the forearms. The front of the collar zips up to cover the mouth, and the single-adjust hood is just big enough for a climbing helmet. The Atom served well as a belay jacket but I wished for at least one internal dump pocket to dry gloves.
The durable water-repellent (DWR) coating has proven extremely durable over the seasons, continuing to bead water long after some of the competitors’ coatings. The Atom AR compresses down to the size of a volleyball.
The Outdoor Research Refuge Jacket is a fully featured, durable, and versatile insulating midlayer. It also works great as an outer layer for moderate activities down to freezing. Plus, the price makes it a great value.
The Refuge uses Outdoor Research’s own VerticalX synthetic insulation. And although the insulation might have elastic properties, the 20 x 30-denier polyester ripstop shell is limited in its mechanical stretch.
Combined with the narrower shoulder dimension, the Refuge Hooded Jacket felt tight across my upper back when active, but the jacket fit my torso extremely well. The arms were a little short for my 34.5-inch arms when reaching forward or overhead. And even though the torso is on the longer side, the lower hem would gap when arms were overhead.
The VerticalX is one of the warmer synthetics. With a light base layer, I could lounge to near freezing comfortably. The Refuge breathes well, allowing hiking around the freezing point with little moisture accumulation. And the DWR coating fended off light precipitation admirably. All these attributes allow the Refuge to do double duty as an outer layer.
The Refuge will stuff down to the size of a cantaloupe, inside a handwarmer pocket with a carabiner clip.
I had subdued impressions when I received the Bight Gear Swelter. It has understated looks, felt bulky, and was in the middle of the road in weight at a verified 1 pound 2 ounces for a men’s medium. But a few weeks later, I found it to be the insulating layer I grabbed most often for moderate-output activity with temperatures near freezing.
Originally, the Swelter felt almost overfilled with 100% post-consumer recycled Polartec Power Fill. But it soon broke in, softened, and shrunk down considerably. The fit is generous and allows plenty of layering room. And the articulated sleeves are just long enough to keep the wrists of my 34.5-inch arms covered in all positions.
The jacket has a long torso, which kept the gap between pants and base layer covered. The front collar is high enough to cover the nose when fully zipped. Breathability was adequate for hiking near the freezing point. And the Swelter packed down to the size of a volleyball. The 20-denier ripstop nylon shell fabric’s DWR coating beaded light precipitation for the duration of the test, which included several wash cycles.
The most useful and impressive feature was the sleeve design at the wrists. A large patch of Polartec Power Stretch Pro at the openings kept them sealed on my small wrists. But a quick push got the sleeves out of the way for stove operation and such. The generous elasticity allowed the sleeves to go all the way to the elbow if desired.
The Swelter’s feature list also includes an elastic drawcord hem, brushed tricot-lined handwarmer pockets in the low position, a mesh interior stash pocket, a zipped mesh chest pocket, an exterior zipped chest pocket, and an adjustable, helmet-compatible hood.
The Prima Lochi Jacket comes from a relatively lesser-known brand that seems poised to make a splash in the outdoor market: Beyond Clothing.
Beyond Clothing uses premium Polartec Alpha insulation often found in active insulating pieces (which you’ll see more of below). But we categorized this piece within synthetic jackets because it’s just too warm for many high-aerobic activities except all but the coldest weather. That said, if you’re getting after it in weather around 10 degrees F and below, well, this could be an awesome choice.
If your activity level is a little more dialed back — say, slowly scaling mountains, snowshoeing, or walking home from work on a frigid winter day — listen up. The Prima Lochi is quite warm, especially for a layer that breathes well. A reversible jacket, it has 70-denier quilted micro-ripstop fabric with a DWR finish and an attached hood. Alone, it should protect from moderate wind and rain.
Put it under a shell in super-cold weather, or heavy wind and precipitation, and you’ll stay toasty warm.
We could see this as a versatile layer for downhill skiing (under a shell) or many mountain pursuits. It’s likely a little on the warm side for backcountry skiing. And the reversible nature adds fabric and weight that you’d probably not want to carry for mountaineering.
The brand also doesn’t make a women’s version of the coat at this time.
But as a great standalone jacket that can handle cold weather as a layering piece, it’s a strong contender. And with exceptional, fast-drying Polartec Alpha insulation, wonderfully smooth zippers, and good-size pockets, this is a layer worth considering if you spend a lot of time outdoors in cold or wet conditions.
Patagonia’s Micro Puff Hoody has drawn accolades and awards from users and media since its release in September 2017. The Micro Puff Hoody is the perfect just-in-case insulating layer that’s barely noticeable in the pack.
The 10-ounce (verified, men’s medium) Micro Puff Hoody kept me warm during moderate level activity down into the mid-30s with just a base layer. And it was surprisingly wind-resistant for such a light garment. Consequently, breathability was on the lower side.
The DWR treatment was exceptional and has continued to bead water after a few wash cycles. The fit is snug, and the sleeves kept my wrists covered — except when my 34.5-inch arms were overhead.
The lack of stretch and the just-to-the waist torso length allowed a little gapping during long reaches. The jacket is very compact, and the slick outer surface makes it ideal for layering underneath shells or heavier layers.
The Micro Puff Hoody will stuff into a handwarmer pocket with a clipping point to just under the size of a cantaloupe. This ability, combined with the best-in-class warmth-to-weight ratio of Patagonia’s PlumaFill, makes it a great always-packed insulator.
The Pertex Quantum GL face fabric proved durable during the test period but does require care, as the wispy fabric is prone to tearing on sharp objects.
Little hits and attention to detail point to the quality construction in this synthetic piece. Sherpa’s trademark, colorful Himalayan designs accent the zipper pull and is stitched inside the chest pocket. Overall, the stitching, materials, and construction look and feel high-quality. And the felt lining in both chest and handwarmer pockets adds a small but much-appreciated touch.
The fit runs a little big, which is worth noting if you plan to layer this piece or not. Those who do layer will appreciate the Annapurna’s taffeta lining. As for the performance, Sherpa uses 3M’s Thinsulate with 75% recycled materials. This well-known insulator worked great as temps varied from 40 and windy down to 20 and snowy. Much beyond that, and you’ll want to add a heavier insulator over it.
But the real selling point for this piece, as with much of Sherpa’s gear, is its eye to social and environmental responsibility. As noted, the insulation comprises 75% recycled materials.
Meanwhile, the shell is made of 100% recycled polyester, and the garment carries both Bluesign and OEKO-Tex certifications for sustainable practices both in manufacturing and materials. And, most notably, every item Sherpa sells helps fund a child’s education in Nepal, from elementary school through college.
Best Active Insulation
GearJunkie delineates insulating midlayers into two categories. The synthetic jacket category (covered above) stresses protection from the elements while this active insulation category incorporates more breathability.
Active insulation works best for stop-and-go pursuits when air permeability while moving paired with adequate protection when stopped can prevent the need to add and remove layers.
The Proton FL has a very trim fit with stretchy underarm gussets, articulated elbows, and high elasticity for excellent mobility with no gapping except for the front lower hem in extreme contortions. This is one of the thinner active insulation jackets tested, which made it fit well under heavier layers. And the perforated inner liner has a smooth finish, which facilitated gliding over a base layer.
The Proton FL felt remarkably warm for its minimal bulk. Arc’teryx’s Fortius 20 shell and Octo Loft insulation struck a great balance between air permeability and protection. I stayed well vented when fast hiking at 40 degrees but still warm during breaks.
The Proton FL has an uninsulated, under-the-helmet hood, fleece-lined handwarmer pockets, two chest pockets, and an adjustable lower hem (with a foam strip to keep it tucked under a harness).
The Ascendant Hoody has a trim but straighter torso cut than others and moderate stretch. The torso length kept the Ascendant tucked under a harness at all times, but the sleeve length exposed wrists during high reaches.
The Ascendant Hoody was the king for high-output activity in colder temperatures. The Pertex Microlight shell and Polartec Alpha Direct joined forces to vent moisture and heat during heavily loaded uphill hiking at slightly below freezing.
Protection and warmth during short water and food breaks were adequate except in strong winds. The fuzzy structure of the Alpha direct wicked moisture quickly off bare skin and base layers. The Pertex Microlight proved extremely water-repellent.
The Ascendant Hoody has zipperless, fleece-lined handwarmer pockets. There is a single chest pocket and thumb loops on the cuffs (but no elastic). The lower hem is adjustable, and the cord lock is positioned toward the rear to clear climbing gear racked on the harness. The single-adjustable, helmet-compatible hood is insulated. Verified weight for a men’s medium is 11 ounces.
The Rime Flex has a very snug fit when still, but class-leading elasticity allowed free movement. The sleeves and lower hem were a tad short for overhead reaches, but the fit around the shoulders felt ample regardless of arm movements.
The Rime Flex is on the warmer and bulkier side of the active insulation category. The Pertex Quantum Air shell and OTI Stretch insulation provided breathability and warmth that worked well for loaded hiking down to the upper 20s. It proved warm during breaks, even in moderate winds. The jacket still performed well into the 30s as long as I vented the main zip, and I found it excellent for lounging into the lower 50s.
The Rime Flex has two handwarmer pockets in the high position, two chest pockets, adjustable lower hem, and dual-adjustable, dual-zipper pulls and an insulated, helmet-compatible hood.
The Helly Hansen Lifaloft Hooded Stretch Insulator Jacket is a surprising piece. While it looks like a standard insulator at first glance, it’s proven itself incredibly quick-drying and highly breathable in 6 months of hard use and everyday wear.
GearJunkie’s editor-in-chief, Sean McCoy, has worn this jacket downhill skiing, skinning in the backcountry, and as a daily wear jacket in Denver’s winter. He also used it as an insulating layer during strenuous elk hunts in the Rocky Mountains. His verdict? The Lifaloft Hooded Stretch Insulator Jacket is a winner.
This layer is light enough to wear under a shell or in conjunction with other layers for a complement to a system made up of a base layer and maybe another light fleece or wool layer. It sits well directly under a shell. It also packs down fairly small (although not as small as down) to stow in a pack.
The jacket has two average-size zipper pockets above the hips and a zippered chest pocket. Two interior stow pockets and a fitted hood round out this versatile layer.
The Ortles Hybrid Tirolwool Celliant Jacket has a contoured, body-hugging fit, with a long torso and long sleeves for coverage in all body positions. Elastic underarm gussets and stretchy softshell sleeves enhance mobility. This jacket was one of the thinner and less-bulky active insulation pieces, making it layer well under heavier garments.
The wool-and-polyester hybrid insulation provided warmth for the core during higher-output activities down to freezing. And the nylon front and back panels blocked wind. The softshell sleeves and sides vented well.
But this hybrid construction made the arms and sides feel much colder than the rest of the body when windy or stopped. The Ortles Hybrid Tirolwool Celliant Jacket was the most comfortable in shoulder season conditions for moderate-intensity pursuits when the core versus arms insulating contrast wasn’t as dramatic.
How to Choose a Synthetic Insulated Jacket
First, take a few moments to envision how you’ll use this jacket. Do you need something for winter climbing or big-mile backpacking? Or will this be a jacket that does it all? There’s no right or wrong answer. But getting clear on the use will help prioritize factors like breathability and durability.
Generally, there’s a trade-off between breathability and waterproofness. If you’ll regularly wear this as an outer layer, it’s worth investing in a bit more waterproofing. But if you’ll use this mainly for high-output activities, look for a jacket that maximizes breathability.
Durability is particularly important if you plan to wear the jacket as an outer layer in rough environments. Most jackets stand up great to the rigors of bushwacking or climbing on rough rock. But some need a bit more care than others.
If you want to thrash about without concern, something like the thinner Patagonia Micro Puff Hoody may not be the best choice.
Sure, you plan to wear the jacket, not just pack it around. But for those times you need to ditch a layer or bring it just in case, the pack size and weight matters. Synthetic doesn’t tend to pack as small as down (although the fill technology is rapidly improving).
And while the Micro Puff may not be the burliest jacket, it wins big time on the packable scale. The Arc’teryx Proton FL is another easy-to-pack choice.
At the end of the day, you want to get a good deal. More than just the lowest price tag, this means a jacket that provides a lot of bang for the buck. Carefully consider how you’ll use it and then look for features to fit. Helmet-compatible hoods, pockets, and materials become important considerations.
Also, if you plan to wear this jacket regularly, it’s worth investing more. Spending a few extra bucks now will afford you many seasons of warmth and comfort outdoors.
Have a favorite synthetic jacket we missed? Let us know in the comments for future updates to this article.