Shopping for outdoor gear for your next adventure is fun. There’s nothing like bringing home a new item to try out on your next trip.
However, when it comes to understanding all of the technical specs, features, and overall outdoor gear lingo, it’s easy to get intimidated.
Choosing between a down vs. synthetic sleeping bag is likely to come up when gearing up for your next adventure. When narrowing down sleeping bags there are so many things to think about from brands and appearance to temperature ratings and materials.
In this article, I highlight down vs. synthetic sleeping bags in detail so you can confidently choose which bag is right for your next adventure.
Table of Contents
Down vs. Synthetic Sleeping Bags — How to Choose?
Synthetic insulation is a manufactured material, which means it does not come from animal-derived down insulation. Synthetic insulation is made from polyester.
In turn, synthetic insulation is quick-drying and continues to insulate even when wet. While synthetic material can retain warmth when wet, it does not mean it’s waterproof. Regardless of the material, synthetic or down, you want to avoid water if possible to maximize warmth and comfort.
Synthetic insulation is in all types of outdoor gear items such as insulated jackets, gloves, sleeping bags, boots, slippers, and more.
Outdoor enthusiasts flock to synthetic insulation for its more affordable price points and its ability to perform in variable weather vs. down insulation.
Synthetic Insulation Specifics:
Pros of Synthetic vs. Down Sleeping Bags
- Wind resistant
- Cheaper than down
- Fast to dry
- Easy to wash/dry
Cons of Synthetic vs. Down Sleeping Bags
- Smaller warmth per weight ratio (i.e. heavier)
- Less compressible (i.e. bulkier)
- Less durable
Types of Synthetic Insulation
There are two types of synthetic insulation: (1) continuous filament and (2) short staple.
Think of continuous as long, continuous strands of filament interlocked together. Due to the woven nature of this insulation, it tends not to migrate within the bag over time, and also provides more durability and loft (warmth) resilience.
Short staple insulation is comprised of short-strand filaments tightly packed together. Short staple feels similar to down filling to the user because it is more flexible, soft, and compressible.
Typically because of the free-floating nature of this insulation, it tends to migrate and break down faster.
If price is your primary factor when deciding to purchase a down vs. synthetic sleeping bag, opting for a synthetic bag makes the most sense.
Opt for a short staple synthetic bag if you want a down feel with increased compressibility. If you are more concerned with the durability and longevity of your bag, consider a continuous filament synthetic bag.
Down insulation is made from duck, goose, or a mixture.
A common misconception is that down is a feather. Down is actually the soft and fluffy under plumage that keeps birds warm during the colder months.
Down insulation is lightweight, compressible, and breathable in comparison to synthetic insulation. The breathability of down is achieved through the trapping of air while still allowing moisture to escape.
Down Insulation Specifics:
Pros of Down vs. Synthetic Sleeping Bags
- High warmth-to-weight ratio (warmer and lighter)
- Highly compressible
- Durable — with proper care, a down bag can last for decades
- Hydrophobic (water-repellant) options are available
Cons of Down vs. Synthetic Sleeping Bags
- Loss of insulating capability when wet
- Slow to dry
- Cleaning requires care
- Not hypoallergenic
- Not vegan
- Higher price
Fill power refers to the measurement of the down insulation’s ability to “loft.” The greater the loft the greater the ability to trap heat.
Fill power is represented by numbers like 600, 650, 750, or 800.
800 fill-power means that one ounce of down fills 800 cubic inches of space. Goose down reaches higher lofts than duck down (up to 900 fill-power), which is why it is used in more premium bags.
To summarize, the higher the number, the higher the loft, which means more insulating capabilities and less weight.
High number = warmer and lighter.
Duck vs. Goose Down
Goose down is traditionally what down bags and jackets are made from.
Due to the increasing costs of goose down, the use of duck down has become more common in recent years. Both materials are tested using the same standards so it is less of a consideration point when choosing which type of down to go with.
Hydrophobic down is down that is treated with a water repellent.
This water repellency helps down to absorb less water and dry faster. It is worth considering hydrophobic down vs. synthetic insulation as it allows your sleeping bag to perform better when wet and allows for quicker drying time.
Other Considerations When Choosing Between a Down vs. Synthetic Sleeping Bag
If you’re still not sure about down vs. synthetic insulation for your next sleeping bag, then consider looking for a hybrid insulated bag.
Some bags are made from differing degrees of both materials to help increase durability and warmth where needed, while also reducing the price compared to fully down-insulated bags.
In addition to choosing between a down vs. synthetic fill for your sleeping bag, consider the following specs:
Sleeping bags come in a variety of warmth ratings.
When thinking about the warmth of your sleeping bag, it is important to consider what your time outdoors will look like.
If most of your time sleeping outdoors is in a climate like Hawai’i, for instance, you probably don’t need a 0° bag. Likewise, if you’re preparing to summit multiple glaciers, you don’t want a bag rated for 45°.
It is safe to add about 10-15° to the bag’s advertised temperature rating. For example, if you are looking at a 10° bag, it will keep you warm in temperatures around 20-25°.
Size and Gender
Sleeping bags are designed differently for men’s and women’s body types.
Typically, women’s bags will be wider in the hips and narrower in the shoulders, while men’s are narrower in the hips and wider in the shoulders.
These differing types of fits allow for more freedom of movement and increased comfort while ensuring thermal retention.
Women’s bags are also often shorter in length than men’s.
Aside from gender-specific sleeping bag designs, there are also different sizes or “lengths” of bags. Finding the right length of sleeping bag is key.
A bag too long will warm up slower, and a bag too short will feel constricting and uncomfortable. Look for X-Long, Long, Short, or Regular options depending on your height and preference.
There are two main types of sleeping bag shapes: rectangular and mummy.
Mummy-style bags reduce spare room. This type of sleeping bag allows for the bag to heat up faster and stay warmer. Rectangular bags allow for more room to wiggle but won’t keep you as warm as a mummy bag.
Additionally, a style of bag that has gained some traction in recent years is sleep orientation-specific bags.
Most bags are designed with back sleepers in mind, but some are now made specifically for side sleepers. Bags like the Big Agnes Sidewinder have a more unique design shape, such as a hood that faces to the side to accommodate the side sleeper.
Zipper Side and Length
Sleeping bags are traditionally designed with left-side oriented zippers — with right-handed people in mind.
This means that when you are lying on your back, the zipper is on the left side of the bag. This allows for your right hand to reach across, get more leverage, and zip it up. This isn’t a deal breaker, so if your chosen bag has a right vs. left-hand zipper — don’t lose sleep over it.
Sleeping bags also come with partial-length or full-length zippers.
The longer the zipper, the easier it will be to climb inside. However, a longer zipper adds weight and decreased compressibility.
Additionally, some bags, like the Patagonia Fitz Roy, have a center zip.
Sleeping Pad Integration
Some brands, such as Big Agnes, design their bags to integrate with their sleeping pads (and even pillows). This feature keeps the sleeper from falling off the sleeping pad in the middle of the night, an important feature for chronic rollers.
Lastly, it is important to consider what your main activity will be for your sleeping bag.
Will you primarily be car or tent camping? If so, then the weight saving and compressibility of down may not be necessary.
Do you spend your summers rafting? If yes, then consider the weatherproof ability of synthetic insulation.
Are you an ultralight backpacker or a bike packer? If this sounds like you, down will provide you with heightened space saving and weight reduction.
There is no right or wrong when it comes to choosing between a down vs. synthetic sleeping bag, only what works best for you and your adventures.
Down vs. Synthetic Sleeping Bag Recommendations
For the purpose of this guide, I am recommending bags in the 20° range.
This temperature range tends to be the sweet spot for three-season camping and backpacking. You will notice that some bags have multiple price points. These price fluctuations are dependent on the size (length) of the bag. A long bag will be more expensive than a regular bag – so make sure you dial in your sizing before making a decision!
Cars provide a little more insulation (and packing space) when sleeping. These recommended bags that into consideration as well as comfort and ease of movement. Whether you are spending the night in your rig or camping out of the car, these bags will fit the bill.
Coleman Kompact 20
The Coleman Kompact 20 is the perfect example of a traditional rectangular “flannel bag” — the sleeping bag you probably took to your first sleepover 20 years ago. However, the bag still boasts synthetic insulation and comes with a stuff stack for ultimate space saving. One of my favorite features is the full-length zipper around the outside so it can also be used as an additional insulating quilt.
REI HunkerDown 20
The REI Co-Op Hunker Down compresses to over half the size of the Coleman Kompact and weighs about half as much.
If you are looking to get a bag that can handle cold evenings, provides an adjustable hood for getting that “tucked in” feeling, and compresses down smaller than most traditional rectangular bags, then definitely check out the HunkerDown series.
HunkerDown gets its name from its use of down insulation in the bags (hence the price jump over Coleman). The HunkerDown 20 boasts 600 down-fill power.
Or, if you want to keep extra warm and share the bed with a partner or pup check out the REI Co-Op HunkerDown 20 Double.
Entry-Level Sleeping Bags
Kelty Cosmic 20 Synthetic
The Kelty Cosmic 20 Synthetic is the synthetic version of our next contender, the Kelty Cosmic 20. This bag is only 3 pounds, and for a synthetic that’s light! This bag is easily the best bang for your buck out there.
Kelty Cosmic 20 (Down)
The Kelty Cosmic Down is a lightweight and affordable budget option for all your three-season needs. This bag will keep you while keeping your pack light and your back happy.
This sleeping bag comes in both women’s and men’s-specific styles.
Mid-Level Sleeping Bags
The North Face Cat’s Meow 20 Eco
The Cat’s Meow is a surprisingly light bag to be a synthetic sleeping bag, weighing in at about three pounds.
The Cat’s Meow is a very popular bag for those looking for a high-performing bag at a reduced price due to its use of synthetic insulation.
NEMO Disco 15
The Nemo Disco is the perfect bag for folks that need a little more room inside the bag, whether you’re a roller or get claustrophobic.
The bag can be unzipped at the “gills” to allow for more temperature regulation and has an internal pocket where you can stuff a jacket or clothes to create a pillow.
High-Level Sleeping Bags
High-end bags can reach prices of upwards of $600. For the sake of this blog, we’ll keep prices within appropriate means so nothing seems out of reach. Most retailers and manufacturers will switch from synthetic to down when making high-end bags due to the space and weight-saving properties.
REI Co-op Magma 15 Sleeping Bag
The Magma 15 is nearly a pound lighter than any other bag on this list, and the 850 fill-power will compress better than any other bag. The zipper design is somewhere between a center and side zip, making it highly accessible when laying on either your side or back.
Down vs. Synthetic Sleeping Bag Final Thoughts
When considering down vs. synthetic sleeping bag options, start by thinking about how you will most often use your bag and the typical weather conditions you’ll find yourself in.
As for brands, there are so many great options for sleeping bags it can be hard to choose which one to go with. Instead, focus on your personal preferences.
If you like the idea of an integrated sleep system consider matching your bag to your pad. If you’re a side sleeper, consider a side sleeping-specific bag. Another addition you can make to your sleep system is a bag liner, such as the Cocoon Microfiber Mummy Liner. A bag liner allows you to wash the liner and not your bag, increasing the lifespan of your bag.
Lastly, don’t forget to let your bag out of its compression sack after each trip so you down over-compress it. Letting the bag rest and expand helps it last much longer.
At the end of the day, there is no right or wrong in the debate of down vs. synthetic sleeping bags — only what works for you.
Are you in the market for a new sleeping bag or looking to purchase your first one? If you still have questions, leave me a comment in the section below.
For more information on overall gear, check out my complete Backpacking Essentials guide.
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