When shopping around for an insulated jacket or a sleeping bag, you'll see words like down and synthetic used. There are a few key components to factor in: warmth, water resistance, and its ability to compress. But what does it mean to get one or the other and how do you decide what is better for you?

Down Insulation

While many believe that down insulation is the feathers of a bird, it actually comes from the plumage found underneath the feathers of geese or sometimes duck. Down works in a way that allows air and body heat to be trapped while maintaining breathability when you sweat. Many prefer down when trying to save space and weight, or when in dry conditions.

Most down is goose as goose tends to be a higher quality, but due to rising prices, some companies have started using duck as well. In recent years, you'll see many companies using down that is RDS, Responsible Down Standard, certified. This means that the geese and ducks are not live plucked or force fed and are humanely treated following the Five Freedoms. 

What many talk about when looking at down is the items weight and compressibility.When looking at a down jacket or sleeping bag, you'll see a number associated with the down, such as 600 fill, 750 fill, or 900 fill. This is called fill-power. Higher fill-power down will weigh less and is warmer than down with lower fill-power. It will also pack down more. One of the biggest misconceptions is that a higher fill-power jacket will automatically be warmer than a lower fill-power jacket. How much down was used plays a big piece in this. Depending on how much, a 600 fill piece could be warmer than an 800 fill piece. For more on fill-power, read this article discussing what exactly all these numbers mean. 

The Ghost Whisperer from Mountain Hardwear: a 6.9 oz jacket with 79 grams of 800 fill down and DWR waterproofing that packs down into its pocket.

When do you want to buy down? 

Down is popular for those looking to save on space and weight. Down is highly compressible, meaning you can shove it into a small space. Thru-hiking, mountaineering, backcountry skiing, climbing, and backpacking are all types of activities that one might benefit from a lighter jacket or sleeping bag, while saving space for more needed gear. A down sleeping bag compresses down significantly more than synthetic, saving much needed space.

A down jacket works well too when you are working up a sweat. Since down offers more breathability and has better moisture wicking properties than synthetic, down jackets are the go-to when you know you'll be sweating a lot at some point.

When do you want to avoid it?

If it has the chance of getting wet, you'll want to go for synthetic insulation. Down clumps together when it gets wet, losing its loft and therefore its insulating properties. When this happens, the insulation is almost useless until it dries out, which can take a long time. Those who spend most their time outdoors on the coasts, rain forests, or other rainy environments are better off using synthetics. Down is also not hypo-allergenic, though this rarely causes issues as it is enclosed.

While more and more down has been treated and is hydrophobic, it still will lose insulation properties once the down gets wet enough. Jackets and sleeping bags with hydrophobic down can see slight moisture to them, but when exposed long enough, the water resistant treatment eventually can't withstand the water and the down will get wet.

Caring for down products

If you use your product enough, your jacket or sleeping bag will eventually need to be washed. Washing down requires a bit of extra care. It can only be washed in a front loading washing machine. Top loading machines usually have a spinner in the middle which can rip the jacket apart. Many  use NikWax's Down Wash to wash their down products, but any detergent meant for cleaning down can be used. When you dry it, it needs to go in a dryer on the lowest heat setting. Throw a couple (clean) tennis balls in to break apart the clumps of down, otherwise the down may leave spaces in the jacket that allows heat to escape. 

You also shouldn't store your down products compressed. Keeping them compressed breaks down the lofting ability of the product. Store your jacket on a hanger. Sleeping bags can be put in a giant sack (most come with one) or hung on the loops attached to the bag.

Two 15°F sleeping bags, both the same length. The bag on the left is a synthetic bag (Lamina Long from Mountain Hardwear) and weighs 3lbs. The bag on the right is a down bag (Rook Long from Mountain Hardwear) and weighs 2lbs 6oz.

Synthetic Insulation

Synthetic insulation tends to be popular for those looking for a lower price point. Synthetic typically consists of polyester.   Every company calls their synthetic insulation something different, so it can be a little confusing when shopping around. Typically, if it doesn't have a fill-power associated with it, the product will be synthetic. Until recently, synthetic used to not be able to breath as well as down, but more and more companies are coming out with newer fabric technologies that allow better breathability and moisture wicking. 

The weight for synthetic will greatly determine how much warmer piece is compared to another. One thing to look out for when buying synthetic is the type used. Some pieces are made up of finer strands of polyester packed closed together. These are the pieces that more closely resemble down. It mimics down in its compressibility and softer feel. It isn't as durable as the insulating pieces that use continuous strands of polyester. The finer strands can also move around, which leaves less insulated areas that allows heat to escape.

When do you want to buy synthetic?

Synthetic comes at a lower price point than down, so synthetic pieces then to be the way to go for those still unsure if they like an activity or for those who need to stay at a lower budget. If you plan on only car camping, a synthetic bag will do you just fine, while leaving money for other needed items.

If you know there is a good chance it may get wet, synthetic retains its insulating properties better than down when it gets wet. It also dries out faster than down. A synthetic sleeping bag is a better choice for activities like pack rafting, or overnight trips on the river. Or for those who want to camp under the stars, even though it might rain.

Synthetic is also naturally hypoallergenic for those who cannot use down. Synthetic typically tends to be vegan as well, so those looking to avoid animal products should look into items made with synthetic insulation. Of course, other animal products could be used as other materials, so be sure to read the labels if this is something that is important to you.

The Nano Puff from Patagonia: A 10 ounce jacket with 60 grams of synthetic insulation and a DWR finish that also packs down into its pocket.

When do you want to avoid it? 

Synthetic doesn't compress as well as down, and it has a higher weight to warmth ratio. This means the item will weigh more to achieve the same warmth as a down item. Backpackers may find that synthetic sleeping bags don't fit as nicely into their pack as a down one. They are also heavier, so if you are looking to cut weight, a synthetic bag is not your best option. Those who have very little space for a jacket in their pack, may also find down insulation suits their needs better.

Synthetic is also less durable than down. Those who use the item a lot should know that every time the item is compressed, the insulating power is slightly reduced. It also tends to not breathe nor wick moisture as well as down, so those who are more active may look more towards down products to keep them warm.

Caring for synthetic products

Like down, synthetic needs to be cared for to maintain its insulating properties. When compressed for too long, the fibers break down more, so store synthetic sleeping bags as you would down ones, either in a large, breathable sack, or hang it by the loops. 

Wash the items the same as down items, but use a tech wash over a down wash. Dry it the same as well to help it the insulation stay evened out. Turn the bag inside out as well to help with the drying process. 

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