Down vs Synthetic Insulation: Which One is Better and Warmer?

If you’re looking to buy a summer sleeping bag or a puffy jacket, you’re going to have to make a major decision;

Down or synthetic?

While pundits have argued the merits of down and synthetic insulation for decades, we’re here to settle the debate over which is better once and for all. 

On this page, we’ll take a deep dive into the world of synthetic and down insulation to help you decide which is best for your needs.


Neither down nor synthetic is best in every situation, though there are some environments where one is preferred over the other. 

If you’re camping in relatively dry locales where weight savings and packability are of the utmost importance, stick with down. 

Otherwise, for wet conditions and cost-effectiveness, synthetic fill is your best choice.,

Page Contents

What is down insulation?

Down is a type of insulation found in sleeping bags, puffy jackets, and other pieces of outdoor gear that’s made from the plumage of birds, like geese and eider ducks.

It’s been used for warmth for hundreds of years in northern civilizations due to its impeccable insulating abilities.

Designed to keep you warm in chilly temperatures like you’d find in Glacier National Park in the winter, down insulation is known for having a great warmth-to-weight ratio. 

This is especially true if you invest a good chunk of change in a high fill power down (e.g., 950 fill down), which can provide an exceptional amount of warmth at just a fraction of the weight of synthetic alternatives.

What is synthetic insulation?

Synthetic insulation is a type of manufactured insulating material that’s made from very thin polyester fibers

These fibers are clustered together to mimic the puffiness of down plumage, allowing them to trap in heat and keep you warm in cold conditions.

Although synthetic is now pretty popular, it is a fairly recent invention, having been first patented under the name PrimaLoft in 1986. You can find synthetic fill marketed under a wide variety of names, including Thermoball, Thinsulate, Coreloft, Polarguard, and Enduraloft.

These days, even though it has a lower warmth-to-weight ratio than down, synthetic insulation is a popular choice for outdoor recreation because it is affordable and functional in wet environments.

What is hybrid down insulation?

Hybrid down insulation, (a.k.a. down/synthetic blend), is a very new type of insulating material that combines the best of down and synthetic fills.

There are two types of hybrid down sleeping bags and jackets.

The first type blends the two materials together throughout the product. Meanwhile, the second type uses both down and synthetic, but in different places, such as down on the top of a sleeping bag and synthetic on the bottom.

While this type of insulation isn’t as common, it does allow for a decent warmth-to-weight ratio and water-resistance without the high cost that often comes with a traditional down sleeping bag or jacket.

So, hybrid down products are a nice compromise for people who love down, but not the price tag.

Price comparison

The very first thing that campers notice when shopping for insulated clothing or camping gear is the big price difference between down and synthetic products.

In general, high quality down equipment costs much more than its synthetic counterparts. This is partially because ethically sourced, high fill power down is found only on mature adult geese, which are expensive to raise.

Meanwhile, synthetic fills can be produced in a factory, which can make them just a fraction of the price of down alternatives.

Winner : Synthetic because your average synthetic jacket or sleeping bag will cost substantially less than a similar-quality down model.

Warmth to weight ratio

An object’s warmth to weight ratio is an informal comparison of how well it insulates compared to its overall weight and bulk.

Although synthetic insulation has come a long way in terms of warmth to weight ratio over the years, even the best synthetic fills on the market are no match for down. Indeed, a 20ºF (-6ºC) down sleeping bag will almost always be substantially lighter than a synthetic model with the same temperature rating.


It all has to do with down’s ability to effectively trap air and heat inside its thin, wispy fibers. While synthetic fills are manufactured to mimic this characteristic of down, they’re just not as effective at trapping in warm air.

Winner : Down because down is much more effective at insulating than synthetic fill, so you can achieve the same amount of warmth with significantly lighter down gear.


If you’re backpacking or if you have limited space in your hiking backpack, having gear that compresses down into a compact size is ideal.

Even though down looks poofy and fluffy in your winter sleeping bags and jackets, it’s actually one of the most compressible insulating materials on the market. When compared to a synthetic sleeping bag, a down bag with the same temperature rating will almost always pack down into a much smaller size.

This enhanced compressibility is a result of down’s better warmth to weight ratio. Since manufacturers can use less down to achieve the same amount of warmth as you’d get with a similarly-rated synthetic sleeping bag, down models are generally much more compressible, making them better for expeditions in remote environments.

Winner : Down because its better warmth to weight ratio makes it much more compressible than its synthetic counterparts.

Water resistance

Unless you happen to be camping in the desert, chances are pretty high that you’ll encounter some moisture during your camping trip.

Whether it’s rain or just condensation inside your tent, however, water can quickly dampen the insulating ability of your sleeping bag or jacket. This is particularly true with down-filled garments and gear as down has no insulating ability at all when it’s wet.

Synthetic fills, on the other hand, are able to keep you warm, even when they’re soaking wet. Although there are some water-resistant downs out there, they pale in comparison to their synthetic brethren.

Winner : Synthetic because it retains its insulating abilities, even when sopping wet while down loses all ability to keep you warm in wet environments.


In general, down insulated garments and sleeping bags last longer than synthetic alternatives.

That’s because the fibers within synthetic insulated gear tend to break down fairly quickly, particularly after years of frequent packing and unpacking your sleeping bag or jacket into a stuff sack or backpack.

Winner : Down because it is more resistant to wear and tear, even after years of use in harsh environments.

Ease of maintenance

Washing sleeping bags, hammock underquilts, and other types of insulated gear can seem like a daunting task, especially if you’re a frequent camper. Therefore, having gear that’s easy to maintain is of the utmost importance.

Most people find that synthetic insulation is easier to maintain because it is less likely to clump up after you wash it. Clumped up insulation is particularly problematic because it can lead to the formation of empty spaces in your sleeping bag or jacket which provide minimal insulative value.

Although washing a down sleeping bag or jacket isn’t exceptionally challenging, it can sometimes require a bit more care and effort, especially during the drying process.

Winner : Synthetic because you can put most synthetic garments in the wash without the need for extra precautions to protect its natural loft and insulation abilities.

Ethical concerns

In recent years, the ethical considerations of outdoor gear have become increasingly important as campers around the world start to search for more sustainable ways to get outside. 

Down has become a hot topic in this regard as down is sourced from ducks and geese, which is a concern for some campers.

For folks who want to avoid animal products altogether, synthetic is the way to go. However, many manufacturers now use only down that’s certified to the Responsible Down Standard (RDS), which ensures that ducks and geese that produce the down that’s used in our gear are treated humanely.

Winner : It depends. If you’re looking to avoid animal products, stick to synthetics. If you’re okay with animal products but want them to be humanely sourced, opt for gear that only uses RDS down.

Examples of camping gear

Looking for a new insulated gear? 

Here are some different pieces of gear that use down, synthetic, and hybrid down insulation.

Sleeping bags

Sleeping Bags

Sleeping bags are perhaps the first thing that people think of when they think of down and synthetically-insulated gear. 

A sleeping bag is a must-have piece of gear for any outdoor adventure, so it’s important that you choose a bag that’s appropriately insulated for the expected conditions on your upcoming camping trip.

For example, something like the ALPS Mountaineering Fusion 40, which has a mix of RDS-certified 600 fill down and TechLoft Micro synthetic insulation, is ideal for campers that want an affordable bag that performs decently well in all applications.

Meanwhile, the ultralight Therm-a-Rest Hyperion 32 and its 900 fill Nikwax Hydrophobic down provide exceptional warmth without any extra weight or bulk. 

On the other hand, a synthetic fill option, such as the NEMO Tempo 35 is a solid choice for cost-conscious campers that often visit rainy environments.

Hammock quilt

Hammock Quilt

Hammock quilts are perfect for anyone that’s trying to hammock during the chilly nights of the spring or fall. These quilts insulate the underside of your hammock, preventing heat from escaping into the chilly air around you.

Synthetically-filled underquilts, such as the EVO Vulcan, are great when cost-effectiveness and weather protection are your biggest concerns. 

On the other hand, pricier down-filled models, like the ENO Blaze Hammock Underquilt, provide an exceptional amount of warmth at just a fraction of the weight.

Read More : 15 Tips and Tricks for Better Hammocking Experience


Puffy Jackets

Puffy jackets allow you to stay warm and toasty on chilly days without the need for bulky materials, like fleece or wool. However, whether you opt for a down, synthetic, or a down hybrid model makes a sizable difference in your outdoor experience.

The Patagonia Down Sweater Hoodie is an absolute classic down jacket, featuring ethically-sourced 800 fill power goose down inside a rugged water-resistant polyester shell.

Alternatively, the Patagonia Nano Puff Insulated Hoodie takes the same great construction of the Down Sweater but uses recycled 60g PrimaLoft Gold Insulation Eco insulation to provide a similar amount of warmth at a lower price point.

For folks who want the best of both worlds, the Arc’teryx Cerium LT Hoodie is a solid choice. Although the bulk of this jacket has 850 fill RDS certified down, Arc’teryx also strategically placed Coreloft synthetic insulation around the arms and cuffs to increase weather-resistance in moist environments.


Hiking Gloves

There are thousands of different models of hiking gloves out there, each designed for a specific type of outdoor pursuit. That being said, with gloves, which tend to get wet quickly, it’s very important that the type of insulation you choose matches up well with your intended use.

For example, a set of down insulated gloves, such as the 650 fill Outdoor Research Transcendent Mitts are best if layered under a waterproof mitten shell for extreme cold camping environments, such as winter in Sequoia and Kings Canyon National Parks.

On the flip side, the PrimaLoft filled Arc’teryx Fission SV are perfect for use in very wet locations while the hybrid down Outdoor Research Stormbound Sensor gloves provide a good mix of water-resistance and warmth in the mountains.

Gaby Pilson

Gaby is a professional mountain guide with a master’s degree in outdoor education. She works primarily in the polar regions as an expedition guide, though she can be found hiking, climbing, skiing, sailing, or paddling in some of the world’s most amazing places when not at work.