What are the best conditions to use a synthetic sleeping bag vs a down one? Can you always use a down sleeping bag as long as you keep it in a dry waterproof bag?

  • Are you assuming that down is superior in most ways, and wanting to know if there is a specific situation in which having a synthetic sleeping bag would be helpful? I have often wondered this myself. Commented Jan 26, 2012 at 11:54

3 Answers 3


The answer is very dependent on the prevailing weather conditions where you are active, and what your budget is



  1. Lower overall price.
  2. Maintains thermal properties when wet.
  3. Does not reduce loft in high-humidity/ sweaty sleeping conditions.
  4. Easier to clean.


  1. The loft does not last as long as down (3-5yrs vs 8-10yrs)
  2. Does not compress as small as down.
  3. Higher weight to loft ratio. (Compared to 650+ down fill)
  4. Retains smells more than down.



  1. Very warm for the weight.
  2. Long life of product.
  3. Compressibility.
  4. Distribution of insulation is near equal over the bag surface.


  1. Price is higher than synthetic (50-100% for same temperature rating)
  2. Cleaning and maintenance. (Special soap, washing, and drying)
  3. When wet the loft is practically useless.
  4. Absorbs some moisture from the body during sleep.


Given that I have used both styles, and love them both in different conditions I would say make your decision after considering the above and speaking with local experts who have used the product in your climate area. Knowledge from a local makes all the difference.

  • 1
    Another disadvantage of down is that you need to make sure the down is evenly distributed as it can end up all in one place whereas the synthetic options are more similar to fabric so they don't bunch up. A good way of re-distributing the down is to put the bag in the dryer (with cool air) and add a few tennis balls.
    – Shawn
    Commented Feb 6, 2012 at 23:55
  • If down get's wet it can rot too (as it's an organic material) where as synthetic's (being made of plastic) don't.
    – user2766
    Commented Jan 6, 2015 at 10:44

Can you always use a down sleeping bag as long as you keep it in a dry waterproof bag?

This appears to be a slight misunderstanding. The problem is not keeping the bag dry when transporting and storing it. The problem is mostly condensated moisture and water vapour from your body.

For example when you sleep in a tent in the winter, there’s a lot of condensation on the tent walls. Some of it drops down and if you’re not careful, your bag could be wet after a few nights unless you can dry it somewhere. With bivy sack the situation can be similar. This can be solved with a membrane down bag that’s got a waterproof fabric on the outer side that will not let any water in.

And then there’s moisture from your body. For example if you stick your head into the sleeping bag and exhale into it, that’s quite a lot of moisture that will again condense somewhere in your down insulation and will build up day after day until you can dry the bag.

These are issues that many people never encounter, not sleeping outside in the winter, knowing how to work around them or staying out just shortly so that the moisture does not have the chance to build up that much. Which is why I agree with Dangeranger in that you have to know what you are going to do with your sleeping bag.

I’ve had about three synthetic sleeping bags, the last one very fluffy and warm. But when I recently bought a down sleeping bag for my girlfriend, there’s no coming back, my next bag is going to be down. It’s much smaller, warmer and lighter, and I haven’t run into any issues with it yet.


Goose-down bags are lighter and more durable as the insulation holds up MUCH better to compression than synthetic.

If you are going on long treks and really need to watch the weight, then a goose is probably better suited. However, keep it dry! Keeping it in a waterproof bag (as you suggested) is a must.

If you don't really go camping much (once or twice a year at best), I wouldn't spend the money on a goose.

The goose-down really has two major downfalls:

  1. Price
  2. Very little warmth/insulation if they get wet. (they also take longer to dry)

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