When you’re out shopping for a new sleeping bag, chances are you’ll come across two main options when it comes to the insulation. One is goose down, while the other is synthetic. Sometimes you’ll come across duck down as well. Insulation is important, because the type of insulation will have a direct impact over things like weight, warmth, water resistance, and of course price.
And while some might make the argument that a down filled sleeping bag is always better, we believe it’s worth giving synthetic ones a shot, too. They do have advantages that might be important to you, so let’s take a look at both and see how you can decide what sleeping bag fill is best for you.
What is Down Insulation?
Even though you’ll commonly come across the information that down insulation is made from the bird’s feathers, that is actually not true. Down is the plumage that you can find beneath the exterior feathers on birds such as geese or ducks. It’s made of fluffy, soft filaments, and while some products will combine this with feathers, down is actually different than feathers.
The way down works when it comes to insulation is by trapping the air inside. This is why it’s so effective, and this is why it’s also incredibly easy to compress. It gets you great breathability and is rather durable, especially when you factor in the competition. And for this reason, if your priority is great performance in cold or dry conditions, or you want to save space and reduce weight, down is undoubtedly the better choice.
Duck Vs Goose Down
While down is typically sourced from geese, goose down has been coming up in terms of pricing recently. This is why some major manufacturers, in an effort to save a bit of money and offer better value with their products, are moving to duck down. And while for the most part, the performance and testing is pretty much the same, which means you get more or less the same quality, the thing with goose down is that it’s capable of achieving a much higher fill-power rating. This is how much the down can loft and trap heat.
The fill power is calculated by measuring how many cubic inches an ounce of down creates at its maximum loft in a testing device, and a 600-fill-power down, for example, indicates that an ounce of that down will fill 600 cubic inches of space. Some of the more premium goose down can reach numbers of up to 900, or even higher. On the other hand, you’d be hard pressed to go upwards of 750 or 800 with duck down.
The advantage here is that a higher fill power down actually needs less down to fill up the space, and achieve higher temperatures, which results in a lighter product. For example, a bag that’s rated at 30 degrees Fahrenheit filled with 600 fill power down is much heavier than one with 900 fill power down, provided everything else is identical.
What Is The Downside of Down?
The downside of down insulation is the fact that it could clump up and lose some of its insulation properties when wet. Of course, premium manufacturers tend to deal with this with water resistant applications down to a microscopic level, but you should still try to keep it dry. And, of course, we have to mention the price – goose down is more expensive than synthetics.
Therefore, wet climates may make more sense for synthetic materials, and if you are going to use down in a wet climate, you better invest in a bag that has waterproofing technologies to keep your down dry.
In Summary, here is a quick pros and cons list of down:
- Warmer than synthetic on a per weight basis.
- Down is more compressible and can pack smaller than synthetic
- Down is extremely durable and can last for a long time.
- Down does not do well when wet. It will lose a lot of insulating power
- Down takes a long time to dry if it does get wet
- Down is more expensive than synthetic
- You’ll need to clean your down bag with special methods – see here
- If you have allergies to down, you’ll want to use synthetic
What About Synthetic Insulation?
Synthetic insulation, on the other hand, is pretty popular as an overall strong performer in a variety of conditions, but more importantly for many, its price. Synthetic fill is usually made of polyester, which is why it insulates even if it’s wet – something you won’t get from down. The price is a big factor, too, and there’s also the durability which is decent, but not on down level.
With synthetic insulation you have short-staple, and continuous filament. Short-staple insulation comes with shorter strands that are densely packed, which is why the bags feel flexible and soft. On the other hand, continuous filament, although it feels a bit stiffer, eliminates the possibility of cold spots by using a thicker, continuous filament.
A synthetic bad will have to be heavier and larger to have the same warmth as a down bag. Therefore, certain scenarios make the greater investment worth it, while others may elect to go with synthetic.
Quick Summary Of Synthetic
- Water resistant, and still insulative (warm) when wet
- Less expensive than down options
- No allergy concerns
- Heavier than down bags of the same temperature rating
- Cannot compress as much so the pack size is larger
- Not as durable as down. Stuffing your bag many times will eventually degrade the insulating properties.
Which One is Right?
Even though there is no clear cut answer as to which type of insulation is better, one thing can be said for certain. If money is not a problem, and you need a sleeping bag that performs good in dry conditions, a down-filled sleeping bag will get you higher temperatures at a lower weight, and with much better when it comes to compression to small sizes.
Of course, goose down does come with a hefty price tag, but if you want premium quality, it’s certainly worth it. If you don’t want to pay too much, however, you could probably do with synthetic insulation. Yes, it will probably be a bit heavier and might not hold warmth as much, but you’ll be saving quite a bit of money, and you won’t have issues if your bag gets wet.
Here are some key considerations when choosing:
Is It A Wet Climate?
In a wet climate, you may want to considera synthetic option. For instance, if you are backpacking in an area where it is supposed to rain nearly every day, and there is the potential for getting wet, you’ll need to:
- Have a down bag with water repellant / resistant properties
- Utilize a synthetic bag
- Do an amazing job of keeping everything dry.
How Warm Do You Need The Bag?
The warmest bags in the world are down. If you need optimal warmth for winter or cold climates, you likely need a down bag. If you are never in very cold temperatures, it is possible you simply don’t need a pack that warm, and can elect for a synthetic bad.
How Long & Far Will You Be Carrying The Bag?
If you are going on a long backpacking trip, you may want to save a few ounces by going with a down bag. If you are always hiking shorter, or only doing short backpacking trips, you may not need or want to pay extra to save weight.
Do You Need To Pack Small?
Have a long trip, small bag, or tons of other gear you need to carry? Synthetic bags will be larger than down bags of the same temperature rating. Keep this in mind when deciding.
Do You Have Allergies to Down?
This one is rare, but simple. If you are allergic to down (very few people are), then you should simply elect for synthetic.
Max DesMarais is the founder of Hiking & Fishing. He has a passion for the outdoors and making outdoor education and adventure more accessible. Max is a published author for various outdoor and marketing websites. He is an experienced hiker, backpacker, fly fisherman, trail runner, and spends his free time in the outdoors. These adventures allow him to test gear, learn new skills, and experience new places so that he can educate others. You can read more about him here: hikingandfishing/about