It’s easy — and understandable — to fret about your down gear. Your down sleeping bag will usually be the most expensive thing in your backpack, and you want to eke out its lifespan as long as possible.
One question that often comes up is around compression. Will it damage a down sleeping bag to squash it right down? And how long can you leave it compressed for?
- Down is pretty robust, and you can compress a down sleeping bag really tightly for short periods without harming it.
- It’s fine to keep your down sleeping bag compressed in a stuff sack when you’re hiking from A to B on the trail.
- Compressing your down sleeping bag for longer periods may eventually damage the down insulation, so you should store it loosely when you get home from your camping trip.
Down Is Tougher Than You Think
Down is an incredible substance — the product of hundreds of millions of years of evolution — and one of its most useful properties is its ability to bounce back from compression.
As soon as you release your sleeping bag from its stuff sack, those tiny filaments begin to spread out and loft up, trapping little pockets of warm air and providing remarkable warmth for very little weight.
The down fibers are so fine and flexible that they don’t usually get bent and broken by compression — unlike synthetic insulation, which suffers more damage when you crush it down.
Tests carried out by UK gear manufacturer PHD have even suggested that regular periods of compression could improve the lofting performance of down bags by around 5%.
Compression Often Isn’t the Problem
If your down sleeping bag isn’t bouncing back from being compressed as well as it used to, it’s probably just dirty. Body oils, sweat, dirt, spilled packet soups, and so on will all affect down’s ability to loft up when you pull it out of its stuff sack.
Thankfully, this doesn’t mean that the down is permanently damaged — you can usually restore performance with a wash.
Feathers and down are not the same thing. Feathers are much more brittle than down, and can be bent or broken by compression.
This is important because cheaper “down” will often contain a percentage of feathers.
Not only will this lower-quality down provide inferior warmth for weight, but it’ll also degrade more quickly if you’re regularly cramming it into a stuff-sack. High-grade down, by contrast, can be squashed down for transport without damaging it.
If you’re confused about quality, temperature ratings, and fill-power, check out our guide to choosing the best down sleeping bag.
Compressing Your Down Sleeping Bag in the Field
Generally, it’s fine to compress your down sleeping bag while you’re out on the trail. It’s what the thing was designed for in the first place — and you’ll also usually be getting it out each night to sleep in it, giving the down a chance to recover.
How Long Is Too Long?
A figure that’s often bandied about online is that you shouldn’t compress your sleeping bag for more than twelve hours at a time. However, we haven’t found any clear basis for this.
We’d suggest that — as with so many questions in the outdoors — you’re best off just using common sense. Don’t leave your sleeping bag compressed for days at a time if you can help it, but equally there’s no need to start worrying if it spends a couple days in the stuff sack while you’re flying long-haul.
Manufacturers have confirmed that this is unlikely to cause any damage, so long as you store it properly at home.
Do You Need to Use a Compression Sack?
Seasoned long-distance hikers or bikepackers often don’t bother with a stuff-sack at all. Packing your sleeping bag loosely into your pack (inside the waterproof liner, obviously) lets you cram it into all the little nooks and crannies around your other gear.
Not only does this make more efficient use of your pack space, but it can also mean your sleeping bag isn’t as tightly compressed as it would be in a tightly cinched stuff sack.
While compressing your down sleeping bag on the trail is unlikely to do it any harm, leaving it crushed up for long periods probably will — especially if it’s dirty or damp when you put it away. A sleeping bag shouldn’t be kept in its stuff sack long term.
Ideally, you should unpack your sleeping bag as soon as you get home from a camping trip and make sure it’s stowed away appropriately until your next adventure.
The most important thing is to make sure the sleeping bag is absolutely dry when you put it away.
For long-term storage, you can either hang it up or keep it loosely packed in a cotton or mesh bag. This guide contains everything you need to know about down sleeping bag storage >>
How Long Can My Down Sleeping Bag Be Compressed?
Compressing a good-quality down sleeping bag for a day or two while you’re traveling is fine, but it should always be stored loosely for longer periods.
Can You Compress Down Too Much?
One of the unique things about down is that you can compress it down really small without damaging it — however, you shouldn’t leave it compressed for long periods.
Does Down Work When Compressed?
Down doesn’t insulate very well when compressed — it needs to “loft up” in order to trap warm air, and it can only do that when it has space to expand.
Can You Vacuum-Pack Down Sleeping Bags?
You can, but leaving your sleeping bag compressed like this for long periods may damage the down insulation.