Down Vs Synthetic Sleeping Bags | 4 Pros and Cons

Last Updated on 17/01/2023

Down Vs Synthetic Sleeping Bags

Down Vs synthetic sleeping bags, which is best?

We summarized all the pros and cons of natural down Vs. synthetic fill for sleeping bags to help you answer this question once and for all. Find out which type of sleeping bag insulation provides more warmth, better waterproofing, lighter weight, and compatibility for your camp style.

Down is considered the premium type of sleeping bag fill, and it certainly costs more but is it the best? Not always. Sleeping bags with synthetic insulation are heavier and bulkier when packed, so why are they still preferred by many outdoors people? Mainly because they are more reliable in wet conditions, but there are other reasons too.

Read our complete buyer’s guide using the links below, or keep reading for the pros and cons.

Down Vs Synthetic Sleeping Bags

The main argument for each is this; Down sleeping bags provide the best warmth-to-weight ratio and pack size. Synthetic sleeping bags will keep you warm if they get wet, dry much faster, and are less expensive than down sleeping bags.

One of the two types may be appealing to you, but consider the scenarios in which you will be using your sleeping bag. If you need extreme warmth for freezing temperatures, then down makes the most sense, but if you are sleeping under a tarp in the rainy season, then a synthetic sleeping bag would be a much wiser choice.

synthetic vs down sleeping bag

Natural Down Sleeping Bags

What is natural down? Natural down is the underbelly feathers of geese or ducks, which are ultra lofty, lightweight, and makes the best warmest insulation for sleeping bags, period. While duck and goose down is naturally water resistant, you can get hydrophobically treated down, which uses chemicals to increase and prolong the water resiliency over time.


Here are some reasons to choose a down-filled sleeping bag Vs. a synthetic fill sleeping bag.

  • Lightweight
  • Very Warm
  • Compactable
  • High Loft

Down sleeping bags have the best warmth-to-weight ratio, which means you can have a super warm sleeping bag that doesn’t weigh much. Down insulation compresses down to a tiny size and lofts back up again, which makes it easy to pack and super comfortable.


Here are some reasons not to choose a down-filled sleeping bag Vs a synthetic fill sleeping bag.

  • Hard to Wash
  • Slow to Dry
  • Requires Treatment to Work When Wet
  • Expensive

Down sleeping bags are notoriously difficult to wash without clumping and require special care when doing so. Down is vulnerable to moisture which can reduce performance by up to 90% unless treated with hydrophobic chemicals. If a down sleeping bag does get wet, then it takes a long time to dry out and requires an electric dryer to redistribute the down. Finally, down sleeping bags can cost several hundred dollars in the most extreme cases.

types of sleeping bag for 4 seasons

Synthetic Sleeping Bags

What is synthetic fill? Synthetic sleeping bags are made from man-made fibers like polyester, which are designed to trap warm air the same way down does. Superfine fibers are created to cluster and loft up the same way down does. The fact that synthetic insulation tries to mimic the natural qualities of down is rather telling of which might be the best insulation type for sleeping bags.

There are over a dozen different synthetic insulation brands that work very similarly to each other.

These are the most well know, but there are lots of others too. I would love to see Polartec create a sleeping bag insulation as I love their clothing.


Here are some reasons to choose a synthetic fill sleeping bag Vs a down-filled sleeping bag.

  • Work When Wet
  • Easy To Wash
  • Fast Drying
  • Better Value

Synthetic sleeping bags will keep you warm even if they get soaked. This makes them reliable in cold and wet weather when you won’t get a chance to dry them out. Because synthetic sleeping bag fill doesn’t clump as down does, you can easily throw it in the washing machine and hang it out to dry on a sunny day. Synthetic fill material can be produced on a massive scale and so you save a lot of money vs down sleeping bags.


Here are some reasons not to choose a synthetic fill sleeping bag Vs a down-filled sleeping bag.

  • Bulkier
  • Heavier
  • Less Loft
  • Shorter Lifespan

Synthetic sleeping bags are bulkier and heavier to pack and carry, which is not very appealing if you’re hiking all your gear to your campsite. The fill itself has less loft, which makes it less effective at trapping heat. Over time, synthetic fibers become flattened on the underside of your sleeping bag, which reduces the lifespan and warmth rating even further.

comparing sleeping bag insulation

Natural Down Vs Synthetic Sleeping Bag Comparison

If you still aren’t sure which type of sleeping bag filling is right for you, then decide which features are most important to you and go with the insulation that ticks the most boxes. Here are some definitive answers about which type of sleeping bag is best:

Which Is Lighter?

Down sleeping bags are significantly lighter than synthetic sleeping bags. Most 2-3 season down sleeping bags weigh under 1 kg, while a 4-season down sleeping bag will weigh closer to 1.5kg. Compare that to synthetic sleeping bags, which rarely weigh less than 1 kg, even for the warmer 2-season summer sleeping bags, and there is absolutely no doubt that down sleeping bags are the lightest.

Which Is More Packable?

There is no debate about which type of sleeping bag is more packable. Down sleeping bags will compact down many times smaller than a similarly rated synthetic sleeping bag. Many down sleeping bags will pack down to the size of a small melon, whereas a synthetic sleeping bag will take up around 15-20 liters of backpack space.

Which Is Warmer Per Ounce?

The warmth-to-weight ratio of down sleeping bags is what makes them so appealing. There is nothing warmer per ounce of material, and therefore, there is also nothing lighter. We can’t find a synthetic sleeping bag with a 30ºF comfort rating that weighs below 1 kg. However, we have tested multiple 10ºF down sleeping bags that weigh under 900 grams.

are down sleeping bags warmer than synthetic sleeping bags

Which Is Warmer?

Tie. You can get synthetic sleeping bags designed to keep you warm down to -40ºF, and you can get down sleeping bags that do the same thing. Both work fine. It’s just that one is more lightweight and packable, and the other is more reliable in cold weather. You have to choose which sacrifices you are willing to make, but you don’t get not to choose.

Which Handles Moisture Better?

Synthetic sleeping bags might lose around 10-20% of their warmth if they get wet, but if down sleeping bags get wet, they will lose up 90% of their warmth. This is a big problem for down and the reason why synthetic sleeping bags are still the preferred choice for wet or humid environments. Hydrophobic down handles moisture significantly better than untreated down. However, it is still not on the same level as synthetic fill, which would literally need to be submerged for it to hold onto a lot of water.

Which Resists Moisture Better?

Synthetic insulation is able to resist moisture for much longer than down ever could; however, sleeping bags with down fill have found a way to level the field a little.

Hydrophobic down can be used to improve water resistance, and so can a water-resistant outer shell. GoreWindStopper (GWS) is used on some expeditions sleeping to protect the down inside from moisture getting in. This combination of treated down and durable shell fabric makes it possible for down sleeping bags to compete with synthetic sleeping bags.

drying a down sleeping bag vs synthetic sleeping bag

Which Dries Faster?

Down sleeping bags take forever to dry and often get so clumped that they don’t work properly anymore. Synthetic sleeping bags still take a while to dry but nowhere near as long as down. You also don’t suffer from insulation clumping or migration through the baffles, which makes washing much easier and less stressful.

Which Has Better Temperature Regulation?

Synthetic insulation is perhaps better for summer because it breathes better than down. Down is extremely efficient at trapping heat, so it would be easier to overheat in a down sleeping bag than it would in a synthetic one. Zips are always your friend on a hot night in a sleeping bag, and so long as you have bug netting in your tent, you can stick a leg out to cool down.

Which is Better for Camping?

Down Vs synthetic sleeping bags for camping, which is best? They both work just fine. If you are hiking your gear to your campsite on your back, you will benefit from the lightweight and packable size of a down sleeping bag. If you don’t want to spend a lot of money or don’t plan on hiking your gear very far from the car, then synthetic sleeping bags all the way!

Which is More Durable?

This is a tough question to answer because down sleeping bags will generally last longer in the long run by retaining loft and warmth. However, they are vulnerable to getting wet and having all the feathers clumped together. Sleeping bags don’t require much care and attention to keep them working, but over time they will lose loft and decline in efficiency faster.

Which is Comfier?

This might come down to personal preference as I personally would much rather sleep in a down sleeping bag instead of a synthetic sleeping bag. Many other people find the thickness of synthetic sleeping bags insulation more cushioning. I personally prefer to rely on a sleeping mat for comfort underneath and use my sleeping bag for warmth from above. Each to their own.

Which is More Sustainable?

Down is actually a byproduct taken from the meat trade, so it could be argued that it is more sustainable than creating millions of cheap plastic-based sleeping bags. So long as the birds are treated humanely and so well, they live happy lives and do not suffer when their time comes.

Because recycled materials have gotten so good in the past decade, it is not such a rare thing to see synthetic sleeping bags using 100% recycled plastic. Still, every year hundreds of thousands of synthetic sleeping bags will end up in a landfill unless repurposed in some way. Recycled down is less abundant, but companies like Patagonia are still trying their best to use it where possible.

Which Do You Prefer?

The only time I choose a synthetic sleeping bag over a down sleeping bag is if I am worried about damaging it or getting it wet. We hope you enjoyed reading this comparison of natural down Vs. synthetic sleeping bag insulation materials. Let us know which you prefer in the comments.

Gear Assistant
Gear Assistant

This article has been written and/or edited by Andrew N. 20+ years of hiking, mountaineering, and camping experience, with access to all the latest outdoor gear.

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