Down vs. synthetic insulation: which is better for outdoor clothing and gear?

Insulation is a very important element to consider when choosing winter jackets, sleeping bags and other outdoor items. Your gear will see you through seasons and all sorts of weather conditions, so it’s wise to favour items that will provide maximum comfort, performance, and protection. Should you opt for down or synthetic insulation? Here are a few things to consider to help you decide which is right for you.

Shop women’s insulated jackets Shop men’s insulated jackets

Down insulation

Down insulation is made from the very fine plumage that grows under the feathers of geese and ducks. This light and fluffy plumage has the ability to trap small pockets of hot air, which means it can naturally retain body heat. It is also lightweight and highly compressible. As an insulating material, down has remarkable qualities and provides excellent protection from the cold – which is probably why it is used in so many models of men’s and women’s winter jackets. But down does not stand up well to humidity; it takes a long time to dry and loses some of its insulating capacity when it gets wet.

Understanding down fill

Fill power is a great tool to measure the qualities and properties of down insulation. Usually ranging between 550 and 900, the number indicates the amount of space (in cubic inches) taken up by one ounce (about 28 grams) of down. This gives information on the fill’s volume and, at the same time, on its compressibility and insulating properties. The higher the fill power, the more efficient down is at retaining body heat, and the more lightweight and compressible it is.

When to favour down insulation

Down insulation is best suited for cold and dry conditions. It can resist temperatures well below freezing, provided there isn’t too much ambient humidity.
As down loses some of its insulating properties when damp or wet, it’s best to reserve down-filled clothing, jackets and vests for low-intensity activities that are less likely to make you sweat. For instance, you could wear these insulated garments and outerwear for walks, light hiking, daily commute and errands or hanging out at your favourite camping spot, or you could put them on in between stretches of intense physical activity.
Jackets and other items with down insulation are also ideal for long excursions or any situation where you may want to travel light; they take up little space and add little weight to your back or in your luggage.

Synthetic insulation

Synthetic insulation includes a number of different insulating materials, most of them made from polyester fibres that mimic the structure of down. Like down, these synthetic insulation materials can retain hot air and thus prevent heat loss. They offer moderate to good protection against the cold, and they have the added benefit of being highly breathable and quick-drying. Unlike down, synthetic materials keep their insulating properties when damp or wet. Because their fibres are sturdier, they are also very easy to maintain.

Understanding synthetic fill

Usually, with synthetic fill, the reference point to measure the qualities and effectiveness of insulation is the thickness of the material. It is expressed as a certain number of grams per square metre (sometimes only grams), which is the weight of a one-metre-long and one-metre-wide piece of insulating material. The higher the number, the thicker the fill and the more effective it will be at keeping you warm. For reference, insulation often ranges between 50 and 100 gsm or so for transitional jackets (i.e., spring and fall jackets), while it can go over 200 gsm for certain winter jackets.

When to favour synthetic insulation

Synthetic insulation is perfect for humid climates, changing weather conditions, heavy snow and rain showers, and situations where you are likely to break a sweat. In addition to their great breathability, synthetic materials have quick-drying properties and provide good insulation even if they become damp or wet. A great choice if you’re looking for snowshoeing pants, a winter running jacket or a moisture-wicking sleeping bag to keep you warm on chilly nights in the great outdoors.

Summary table: Down VS. Synthetic insulation

“Mixed” insulation: a combination of down and synthetics

In recent years, specialized companies have been finding ways to combine down and synthetic fibres to maximize their strengths and mitigate their weaknesses. For instance, down and synthetics can be blended in different proportions to create highly versatile insulating materials.

The two can also be spread strategically between different parts of a given item, making it possible to choose the most appropriate insulation for each area. In some Helly Hansen and Rab jackets, for instance, PrimaLoft insulation is used in areas most exposed to precipitation or likely to become damp with sweat.

Other brands combine down and their own insulating materials featuring various properties. The North Face notably integrates its Heatseeker Eco insulating material in some sleeping bag models and in strategic places like the hood, shoulders, armpits and sides of certain down jackets. In some Outdoor Research jackets, areas prone to wear and dampness are insulated with VerticalX Eco, a material made from recycled fibres and modelled on the distinctive lightness and loft of down.

The proper care for each type of insulation

Insulating materials, whether down or synthetic, should not be washed too often. If you notice stains on your gear, you can remove them locally by using a mixture of mild soap and water to gently rub the affected area. Just make sure you avoid contact with the insulation as much as possible to prevent damaging it. That said, over time and with repeated use, all insulation will pick up dirt and eventually become less effective. If your winter jacket doesn’t feel as warm as it used to, or your sleeping bag has lost some of its loft, it may be because it is in need of a good wash.

Caring for items with synthetic insulation

Synthetic insulation requires simple care: wash by hand or in a front-loading machine, using a mild soap or a cleaner made specifically for synthetic materials, then rinse thoroughly and wring out well. Once your item is clean, tumble dry it at a low temperature or lay it out in the sun for a few hours, and you’re done. Make sure you read the care label before you start, though, and always follow the instructions. You should also avoid chemicals such as bleach or fabric softener, which can damage the insulation.

Caring for items with down insulation

Down insulation requires specific – and very delicate – care. If down fibres are damaged or deformed, they will become less effective at trapping warm air, which means they will lose some of their insulating power.
Unless the care label specifies otherwise, wash your items in lukewarm water, either by hand or in a front-loading machine on the gentle cycle. Whichever method you choose, make sure you use a specially formulated product (such as Grangers or Nikwax down cleaners, for example), and rinse your items thoroughly in cold water to remove any residue. Always wring out your items by hand, and be careful never to twist or compress them to preserve the integrity of the down fibres. A good way to do that is to use a plastic basket like a colander and let the item drip for a little while.

Ideally, down-insulated items should be tumble-dried at the lowest temperature setting possible; air-drying is very slow for this type of insulation, and that increases the risk of mould growth. Dry in a series of short cycles, and take your item out of the machine frequently to check that the down is still spread evenly inside, as it tends to clump together when wet (you can also use dryer balls to prevent this). If you notice any clumps of down, break them up with your hands or a gentle shake, then put the item back in the dryer.

If you want to learn everything you need to know on how to care for your clothes so they’ll have a longer lifespan, take a look at our clothing care guide.