12 Best Synthetic Insulation Materials for Outdoor Clothing | Vegan Down Alternatives
Best Types of Synthetic Insulation for Clothing
In this guide to the best synthetic insulation materials for outdoor clothing, we share 12 different types of synthetic insulation as alternatives to down. You will learn which are the most lightweight and breathable man-made insulation types so that you can decide if it works for your needs.
Synthetic insulation is often used for outdoor clothing like jackets, gilets, gloves, and camping gear like sleeping bags. It offers many benefits that down does not and is a way for vegetarians and vegans to avoid using animal products.
Synthetic insulation has always tried to mimic the qualities of natural insulation like down or wool. It gets fairly close but will rarely match the warmth-to-weight ratios of high-quality down or the durability of wool. Nevertheless, here are some of the best synthetic insulation materials you can choose from today.
The biggest advantage of synthetic insulation is that it generally retains more of its insulating ability when damp and dries faster than natural down. This makes it particularly useful for active outdoor clothing, wet-weather gear, and sleeping bags that need to cope with condensation.
12 Best Synthetic Insulation Materials for Outdoor Clothing
Unlike down, synthetic insulation comes in many different varieties. They all do the same basic thing but may be better in certain areas. Like how PrimaLoft has an amazing warmth-to-weight ratio or how eraLoft uses hollow fibres to ensure it works even when wet.
Here is a brief explanation of what each insulation claims to do. Some technologies have been around for decades, while others have been updated or replaced by newer versions. I’ve included the older materials where they are still useful for understanding the insulation found in existing outdoor gear.
PrimaLoft Synthetic Insulation
PrimaLoft insulation is used in many of the best ultralight synthetic sleeping bags because it is similar to down. The clusters of synthetic fibres are composed to behave much the same way as downy feathers by retaining loft and trapping heat. It works even when damp and compresses down very small with the help of a stuff sack.
After reviewing dozens of synthetic ultralight sleeping bags, PrimaLoft is constantly one of the highest performers. Here are some of the different types of PrimaLoft synthetic materials, not including every variation in its expanding eco range.
PrimaLoft Classic (Black, Silver, and Gold)
PrimaLoft Classic is available in three main performance tiers: Black, Silver, and Gold. Black is the most basic version and as such provides the least warmth per gram. Silver PrimaLoft Classic is slightly warmer and more suited for colder but active use.
The most expensive of the three types of synthetic PrimaLoft insulation is the Gold standard, which offers an excellent warmth-to-weight ratio and is perfect for cold conditions where you still want a lightweight jacket.
PrimaLoft Gold has often been compared with approximately 600-fill-power down, although the comparison isn’t exact because synthetic insulation and natural down are constructed and measured differently.
PrimaLoft has also expanded the range with newer materials such as UltraPeak, RISE, and more environmentally focused manufacturing processes. Gold is still one of the names I would look for when buying premium synthetic outdoor clothing.
PrimaLoft Active
PrimaLoft Active has improved breathability, stretch, and moisture management compared to the original PrimaLoft Classic. It is perfect for lightweight jackets that keep you warm but don’t overheat when you’re working hard.
PrimaLoft Active is especially good for insulating the sleeves of jackets so that you don’t get reduced mobility in your arms.
The current Active range includes Gold Active, Gold Active+, Gold Active Vent, Silver Active, and Active Evolve. These are designed for slightly different levels of exertion and breathability.
Active Evolve is particularly interesting because it uses a fabric-like insulating structure designed to manage moisture and body heat while you’re moving.
If you do a lot of hiking uphill, trail running, or ski touring, I would generally look for active insulation rather than the warmest and thickest conventional synthetic fill.
PrimaLoft ThermoPlume
PrimaLoft ThermoPlume is the company’s version of synthetic down, and what makes it so cool is that it can be used in machinery designed for real down feathers.
This means that manufacturers can offer synthetic or down fill without completely redesigning their production process. You simply switch the down-blowing machine to synthetic and fill the baffles as normal.
ThermoPlume is designed to reproduce the loft, softness, and compressibility of down while providing better performance when damp.
There are now several versions, including ThermoPlume+, which improves loft and reduces bulk, along with recycled and lower-impact manufacturing options.
ThermoPlume+ is especially worth looking out for if you want the feel and appearance of a down puffer jacket without using animal-based insulation.
Climashield Synthetic Insulation
Climashield has several variations of its outdoor clothing insulation, but the best for warmth-to-weight ratio is the Climashield Apex. Climashield Prism is also very lightweight and keeps its composition and structure under sustained use and when wet.
Unlike loose-fill synthetic down, Climashield uses continuous filament insulation. Instead of thousands of individual clusters that can move around inside a jacket, the fibres form a connected insulating structure.
This gives Climashield excellent durability and makes it particularly popular for synthetic sleeping bags and quilts.
Climashield Apex Insulation
Climashield Apex claims to be the most lightweight and thermally efficient continuous filament insulation available today. I can’t confirm this, but I do know it sets the bar very high.
It also incorporates AquaBan technology to help it perform in damp conditions.
Apex is popular in lightweight synthetic sleeping bags, insulated jackets, and backpacking quilts because you can achieve excellent insulation without having to stitch lots of individual baffles through the material.
Climashield Contur Insulation
Climashield Contur insulation is a slimmer continuous filament fibre that works better for gloves, footwear, and lightweight jackets.
It is extra breathable and low profile, unlike a puffer jacket which can feel a little cumbersome when wearing a backpack.
Contur is especially interesting when you want insulation that moves with your body rather than a thick layer that restricts your arms.
Climashield Prism Insulation
Climashield Prism insulation is designed to be durable and long-lasting for items you use regularly. These are most often jackets and sleeping bags.
The insulation can be washed and used multiple times and is designed to retain its thermal efficiency over repeated use.
Prism synthetic insulation also incorporates AquaBan water-repellent technology to ensure high performance, whatever the weather.
Climashield Comfort+ Insulation
Climashield Comfort+ has an extra plush feel to it that is flexible and quick to warm up. All aspects of comfort were considered, from how warm it is, to how breathable it is or how it feels next to the skin.
It is designed to provide warmth without making a garment feel unnecessarily stiff or bulky.
Climashield Protect FR Insulation
Protect FR features Climashield’s proprietary thermal qualities and features but with the added benefit of flame-resistant protection.
This makes it a good insulation choice for specially designed workwear and protective clothing.
It is worth noting that Protect FR is an insulating component, not a guarantee that the finished garment is flame-resistant. The entire item of clothing needs to be designed and tested to the appropriate safety standard.
We may see Climashield Protect FR used in more protective outdoor workwear and specialist clothing in the future.
Climashield Combat Insulation
Climashield Combat was initially designed for military and tactical use cases. As you might expect, it is incredibly durable, lightweight, packable, and will work whether it is wet or dry.
It features AquaBan DWR technology to help maintain insulation in damp conditions.
Because of its durability, Combat is also suitable for demanding outdoor clothing and equipment that gets repeatedly packed, unpacked, and compressed.
Climashield Eco Insulation
Climashield Eco is available in high-loft and ultra-thin combinations to suit a wide variety of applications for more sustainable outdoor gear.
Manufactured from recycled plastic bottles, this is one of a growing number of environmentally focused synthetic insulation materials for outdoor clothing.
The Eco range retains the continuous filament design, which is useful for keeping the insulation stable throughout the life of the garment.
Climashield also offers other specialist materials, including HL and Elite, so the range is now broader than the seven variations originally covered in this article.
3M Thinsulate Synthetic Insulation
3M Thinsulate is one of the most commonly used insulation materials for outdoor clothing like gloves, hats, and winter jackets.
It is one of the best-value synthetic insulation types and doesn’t always feature in higher-end synthetic sleeping bags. Thinsulate is moisture-resistant and retains useful insulating ability even when damp.
Like PrimaLoft, 3M Thinsulate is its own product family that is licensed to other brands.
There are multiple technologies with different variations of synthetic insulation for specific applications. Thinsulate also makes water-resistant, flame-resistant, stretchy, and recycled insulation.
3M Thinsulate Original
Thinsulate Original comes in several different varieties, including Type C, Type M, Type O, and Type P.
From what I can understand, they use different fibre structures and constructions to suit different types of clothing. Some versions are designed for thinner garments, while others provide more loft or a different balance of warmth and flexibility.
This is why two jackets that both say they contain Thinsulate can feel very different when you put them on.
3M Thinsulate Advanced
3M Thinsulate Advanced includes different insulation constructions such as Type G and Type KL.
Type G is designed to be lightweight and soft with high loft. Type KL is more focused on durability, warmth, and moisture resistance for demanding clothing applications.
The important distinction is that these materials have been developed for specific performance requirements rather than simply making the insulation as thick as possible.
3M Thinsulate Bedding
3M Thinsulate Bedding insulation is designed specifically for things like sleeping bags and duvet quilts.
There are different varieties, including Type TIB, which uses siliconized fibres, and Type Z, which has a loftier structure intended to mimic down more closely.
These materials allow bedding manufacturers to use synthetic insulation while keeping the product relatively soft and compressible.
3M Thinsulate Featherless
Thinsulate Featherless is 3M’s version of synthetic down. It is super lightweight, fluffy, and efficient for trapping heat.
The original Featherless Type FL600 is designed to perform similarly to approximately 600-fill-power down in certain applications, while Type FL700 is a higher-loft alternative.
Unlike conventional natural down, Featherless retains more of its insulating performance when damp and dries relatively quickly.
Vegans are quite fond of this type of insulation, and recycled Featherless versions are available too.
3M Thinsulate Recycled
3M Thinsulate Recycled has several varieties. Some use the same loose-fill approach as Featherless insulation but incorporate recycled polyester.
Other variations include Type EC and Type EP, designed to deliver warmth while using recycled plastic materials.
3M also offers 75% recycled and 100% recycled Featherless insulation, along with newer flowable Featherless technologies made using recycled materials.
These are particularly interesting because synthetic insulation is traditionally made from virgin plastics, so increasing the recycled content is an obvious way to reduce the demand for new raw materials.
Columbia Omni-Heat Synthetic Insulation
Columbia Sportswear has a wide spectrum of thermal insulation technologies under its belt when it comes to outdoor clothing and camping gear.
Most of Columbia’s insulated jackets also combine Omni-Heat Reflective technology, which is featured further down this guide.
It’s worth distinguishing between Columbia’s actual insulating fills, such as Thermarator, and reflective lining technologies like Omni-Heat. They work together but aren’t quite the same thing.
Columbia Double Wall
Columbia Double Wall incorporates a wind-resistant outer construction designed to retain warmth between two layers of fabric and reduce cold spots.
It doesn’t rely on exactly the same principle as Omni-Heat Reflective, but it can be combined with insulating materials to create a warmer overall jacket.
Some awesome quilted hiking jackets made with Columbia Double Wall aren’t massively warm on their own but are perfect for being active or as part of a layering system.
Columbia Turbo Down
Columbia Turbo Down is a hybrid insulation technology that combines natural down with synthetic insulation.
This provides excellent warmth and performance in colder conditions while using the strengths of both materials.
There is also a version called TurboDown Wave, which was designed to reduce cold spots by alternating the alignment of the insulating baffles.
I bet it is hard to visualize what I mean, so here is a video to explain it:
TurboDown is not fully synthetic, so bear that in mind if you are specifically looking for a vegan alternative to down.
Columbia Thermarator
Thermarator is Columbia Sportswear’s option for synthetic down.
Composed of ultrafine fibres that intertwine with each other to form a kind of tangled cluster, it has an impressive warmth-to-weight ratio.
Just like down insulation, Thermarator can be stuffed into quilted sections for things like insulated jackets and other cold-weather clothing.
Thermarator is still featured in Columbia’s current insulation technology range and is designed to retain useful warmth when damp.
LYCRA Thermolite Synthetic Insulation
Thermolite is made by The LYCRA Company and is a family of polyester technologies that can be used as thin fibres to make things like base layers.
But the fibres can also be clustered together to create thermal insulation materials for outdoor clothing.
The Thermolite EcoMade range includes materials made from recycled plastic bottles and textile waste, which reduces demand for virgin polyester.
The fibres used in several Thermolite technologies have hollow cores, helping them trap air and provide insulation while remaining lightweight.
There are three main variations as follows.
Thermolite EcoMade Insulation
Thermolite EcoMade Insulation is available in thin and high-loft varieties rated with some of the industry’s best warmth-to-weight ratios.
As one of the best synthetic insulation materials, you can expect water resistance, fast drying, low weight, and good thermal resistance.
Some EcoMade versions contain 85% recycled fibres, while newer products use recycled textile waste or entirely recycled PET.
The exact recycled content depends on the product, so it’s worth checking the manufacturer’s specification.
Thermolite EcoMade T3 Insulation
Thermolite EcoMade T3 Insulation is made with at least 35% recycled materials and has improved breathability, is easy to wash, and is lightweight.
But the biggest differentiator is how well it packs down and then recovers its loft.
The fibres slowly but surely spring back into position even if they have been crushed inside a storage bag all day.
There is also a T3 Plus variation with a higher recycled content, giving manufacturers another option when choosing insulation for more environmentally conscious outdoor clothing.
Thermolite EcoMade T-Down Insulation
Thermolite EcoMade T-Down Insulation is a synthetic down and an alternative to natural down jackets and sleeping bags.
T-Down has a claimed fill power of 500, but unlike conventional down it retains more warmth when damp, is fast to dry, and doesn’t clump in quite the same way.
Like T3 insulation, T-Down synthetic down can pack down very small and then spring back to life when taken out.
The current T-Down technology is made from 100% recycled PET bottles, which is an impressive achievement for a synthetic insulation designed to mimic natural down.
Other Thermolite Insulation
Some other products that LYCRA has developed are Thermolite EcoMade All-Season Insulation, which is designed to provide warmth in cooler conditions while managing moisture during more active use.
Then there is Thermolite Infrared Technology, which is designed to capture energy from sunlight and help retain warmth.
Far Infrared Technology has also been developed for socks and other garments that benefit from lightweight thermal fibres.
Fjällräven G-Loft Supreme Synthetic Insulation
G-Loft Supreme is Fjällräven’s synthetic insulation which they use in some of their jackets, like the Padded Skogsö jacket I was testing when I originally wrote this guide.
G-Loft Supreme is constructed from hollow, fine polyester fibres that naturally form clusters like down feathers do.
It is highly compressible, dries quickly, keeps you warm when wet, and can be cleaned regularly without losing performance as easily as some natural down products.
It can also restore its shape after compression.
The version detailed by Fjällräven is made using 10% recycled polyester and has been developed to retain warmth in damp and cold environments.
One of its biggest advantages is what Fjällräven calls the memory effect. The fibres naturally spring back into shape after being compressed, helping the insulation maintain its loft over repeated use.
This is particularly useful for outdoor jackets that spend a lot of time stuffed inside a backpack or being compressed underneath shoulder straps.
The North Face ThermoBall Synthetic Insulation
ThermoBall is The North Face’s sustainable alternative to down, which uses 100% recycled synthetic fill in its current ThermoBall Eco version.
It is incredibly warm, lofty, and compressible for a synthetic insulation.
The microfibres mimic the way that down clusters together to create pockets of warm air.
The benefit ThermoBall has over down, though, is that it doesn’t all clump together when wet and will continue to keep you warm.
ThermoBall Eco uses small synthetic clusters rather than a continuous sheet of insulation. This helps give jackets and other products that familiar puffy-down appearance.
One of my favorite North Face ThermoBall products is their camping slipper mules.
They demonstrate how well this insulation can work in something other than a jacket, especially when you want warm footwear that doesn’t weigh much or take up lots of space in your camping bag.
Marmot Thermal R Synthetic Insulation
Thermal R is Marmot’s own proprietary group of polyester insulation.
Using hollow fibres and multichannel filaments, Thermal R is designed to resist the effects of perspiration, humidity, and moisture while continuing to trap heat when damp.
Marmot also has a more sustainable version of the same material that is made using 100% recycled fibres called Thermal R Eco.
Both have excellent warmth-to-weight ratios and are designed to be durable enough for jackets, sleeping bags, and other insulated outdoor equipment.
The multichannel fibres help manage moisture, while the hollow fibres provide loft without adding too much weight.
It might not be as well-known as PrimaLoft or Thinsulate, but Thermal R is a good example of how outdoor brands develop their own insulation rather than relying entirely on third-party suppliers.
Mountain Hardwear Thermic MX Synthetic Insulation
I cannot find much information about Thermic MX, but I remember having a Mountain Hardwear sleeping bag a good few years ago that used this insulation, and it was amazing.
It appears that Thermic MX is no longer a prominent part of Mountain Hardwear’s current insulation range, but you can still find older synthetic sleeping bags that used it.
For that reason, I would treat Thermic MX as a legacy insulation rather than one you should necessarily expect to find in a new sleeping bag today.
That doesn’t make it bad insulation, though. In fact, there are plenty of older synthetic sleeping bags that perform incredibly well despite having materials that are no longer used in current models.
If you come across an older Mountain Hardwear sleeping bag with Thermic MX, I would pay more attention to its condition, loft, and temperature rating than worry about the insulation being an older technology.
Arc’teryx Coreloft Synthetic Insulation
Coreloft is one of the main insulation technologies used by Arc’teryx, who make THE best outdoor jackets in the world.
I have never seen a sleeping bag made from Coreloft, but it would absolutely work.
It was designed to provide lightweight warmth while retaining its loft and is one of the more compressible synthetic insulation materials used in premium outdoor clothing.
Arc’teryx uses different versions of Coreloft depending on the garment, including Coreloft Compact and other constructions that balance warmth, breathability, and durability.
Coreloft Compact is particularly useful in garments that are repeatedly packed away because it is designed to retain its insulating structure over time.
You will also find Coreloft used in hybrid insulation systems, where down is placed in areas that need maximum warmth and synthetic insulation is used in locations more likely to encounter moisture.
This is a clever way to get some of the benefits of both materials without compromising too much on weight or performance.
Therm-a-Rest eraLoft Synthetic Insulation
eraLoft is one of Therm-a-Rest’s innovative insulation materials created for camping sleep systems.
eraLoft has been used in Therm-a-Rest’s lightweight synthetic sleeping bags and quilts for its ability to withstand being compressed and lofted repeatedly without losing too much performance over time.
Like many synthetic sleeping bag fibres, eraLoft uses hollow-core polyester fibres to trap air and provide insulation.
These fibres resist moisture absorption better than natural down and retain useful thermal performance when damp.
One of the most important advantages of this kind of insulation is that it allows sleeping bags and quilts to be compressed for backpacking without requiring the same level of care as expensive natural down.
Therm-a-Rest has used eraLoft in products such as its synthetic sleeping bags and insulated quilts, although the exact fill materials vary across current and older models.
If you are looking at a particular Therm-a-Rest sleeping bag, check the specification for that model rather than assuming all its synthetic products use eraLoft.
Columbia Omni-Heat Reflective Insulation Technology
Omni-Heat, made by Columbia Sportswear, has several different varieties that use a similar idea at their core.
What makes Omni-Heat different is that it is designed to be used alongside other types of insulation, which may include synthetic fill or natural down.
Strictly speaking, Omni-Heat Reflective is a thermal lining technology rather than a conventional synthetic insulation filling.
It uses reflective materials to help retain body heat while leaving enough space between the reflective elements for moisture and excess warmth to escape.
This is why you will often see Omni-Heat paired with Thermarator insulation or another type of fill inside the same jacket.
Omni-Heat Infinity
Omni-Heat Infinity is one of Columbia Sportswear’s most advanced reflective lining technologies.
It uses gold-coloured dots of reflective material spread across the lining so that it remains breathable.
These dots help reflect radiant body heat while the garment’s other materials provide the bulk of the insulation.
The expanded reflective pattern is designed to improve heat retention compared with the original silver-dot Omni-Heat lining.
Omni-Heat Black Dot
Omni-Heat Black Dot is an external thermal technology that uses a similar circular pattern design on the outside of the garment.
Unlike the reflective lining inside a jacket, the Black Dot technology is designed to help reduce heat loss through the outer fabric.
This can be combined with internal reflective linings and synthetic insulation to improve the overall warmth of a jacket.
Omni-Heat 3D
Omni-Heat 3D uses a unique pattern that combines reflective material with small raised fibres that help improve insulation and next-to-skin comfort.
You may find Omni-Heat 3D used in ski or snowboard clothing where you want a warmer feeling against your body without adding excessive bulk.
The raised fibres also help create a little separation between your skin and the reflective lining.
Omni-Heat Reflective
Omni-Heat Reflective is the standard or original version of Columbia’s thermal reflective lining.
It uses small silver dots to reflect radiant body heat while allowing moisture and excess heat to escape through the spaces between them.
It is lightweight and can make a noticeable difference in a well-designed insulated jacket.
Omni-Heat Thermal Coil
Omni-Heat Thermal Coil is an older variation of the reflective technology which uses continuous reflective lines instead of the more familiar dot pattern.
The idea is similar: reflect some of your body’s radiant heat to improve warmth without relying entirely on thicker insulation.
It is worth including as part of the evolution of Omni-Heat, although Columbia’s current range focuses more heavily on Omni-Heat Reflective and Infinity.
Thanks for reading this guide to the best synthetic insulation materials. Hopefully, you now have a better idea of what all the different technologies actually do and why some are better suited to jackets, sleeping bags, or other outdoor clothing.
If you have a favorite type of synthetic insulation or have noticed a big difference between two jackets using different materials, let us know in the comments.
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