Backpacking Sleeping Bags

I get asked a lot about how to choose backpacking sleeping bags.  Most people are looking for a bag for warmer weather backpacking (i.e., not winter, also known as 3-season sleeping bags) and that is what this post is primarily about. 

If you choose a bag that is good for backpacking, rest assured that it will also be good for car camping but the reverse is not true.  However, if you are only car camping you don’t have to worry about weight and can buy a less expensive bag.

When choosing backpacking sleeping bags, don’t overlook the specifications (specs).  Reading the specs becomes a habit, at least it does if you are a guide.  If the sleeping bag specs do not list weight and stuff size, they probably won’t meet your requirements… or you might have to dig deeper to find more detailed specs.  The following explains some of the specifications:

Temperature Rating

For most 3-season backpacking sleeping bags, a good 20 degree rating is sufficient.  When temperatures drop below 40°, some similarly rated bags will be fine while others might be too cold.  A 30 – 35 degree rated down bag is also a great solution and more often true to the temperature rating. 

• The actual warmth of similarly rated bags varies widely so you should research legitimate user comments and reviews.
• Some manufacturers exaggerate how warm their bags are.·
• Many sleeping bags will be listed with two or more different types of temperature ratings (e.g., survival rating, comfort rating, upper and lower limits, etc.).·
• In many cases the highest temperature rating is the one that will have the most meaning for the user who is sleeping in it.  I have a couple of old 20° synthetic bags that are cold if the temperature gets much below 55°.  That’s because the synthetic insulation compresses over time and doesn’t trap as much insulating air.  I keep them around for car camping in hot weather.
• Down tends to maintain its “loft” much longer than synthetic bags and a good down bag can last a long time if taken care of.

Weight / Packed Size

Two specs to consider when selecting backpacking sleeping bags are the weight of the bag and the amount of space it takes up when stuffed into your backpack (the “stuff size”). 

• For a three-season bag aim for 4 pounds or less, 3 pounds is good for a synthetic bag.  Two (2) pounds or less is ultralight and probably down (a good choice if you want to spend that much).  That is because down fluffs better than synthetics and therefor a smaller weight of down will yield the same warmth (and it compresses smaller when in your backpack)..
• For 3-season backpacking, I look for “stuff sizes” less than about 8 x 18 inches.  Bigger than that and it may be too big for your backpack.  6” x 12” or so is very good, but 8x 17 (for example) will be good enough for most people.  “Stuff Size” usually refers to the size of the stuff sack provided with the bag.  Some bags might be able to be compressed a little smaller, but for most bags the stuff size is the metric to use when choosing.  Compression sacks have buckles to really squash down a sleeping bag, but if you need one to fit the bag in your backpack, the bag you are compressing may also be too heavy for most backpacking duty.
• Most sleeping bags come in two sizes (regular and long).  For men, regular fits up to a height of 6 feet and long sizes fit up to 6’6”.  It may vary among manufacturers, but they usually have a size chart to go by.

Length:

Sleeping bags commonly come with men’s sizes described as regular (fits to 6 feet tall) and long (fits to 6’ 6”) and women’s sizes described as regular (fits to 5’6’) and long (fits to 6’) .  Some manufacturers may have different variations of sizing.  One well known outdoor goods manufacturer makes a range of men’s sizes but only one size for women (“regular”) that fits up to 5’ 8”.  It is an unfortunate reality that the tallest men and women have fewer choices.

• If a bag is too big, there will be more air in it for your body to heat which will make it a little colder.  If it is too small, you will compress the insulation more, making it colder.  A little too big is better than a little too small.  If you are 5”10, you can go with a regular (male sizing).  If you are 6” 2”, its best to go with a long.
• A little extra room in the foot bed can be a convenient place to finish drying clothes (such as the days damp tee-shirt).  I get residual moisture out of socks by placing them over my chest.  I hardly notice that they are there, and they come out in the morning dry and warm and ready for a second day of use.

Material (down vs synthetic insulation)

Down is my favorite, but it will not keep you warm if it gets wet.  However, I use down sleeping bags and have never gotten them wet.  It is pretty easy to keep your sleeping bag dry. Synthetic insulation will still insulate a bit when wet and dries faster than down.

• Down bags are more expensive than synthetic bags.
• A couple of manufacturers have a down bag that doesn’t have insulation on the bottom, but instead a sleeve that integrates with a sleeping pad.  While there are some reasons that this makes sense, there are also possible downsides and I think it is a bit gimmicky.  It might also lock you into needing to buy a pad from the same manufacturer.

Shape of the Sleeping Bag

“Mummy” shaped backpacking sleeping bags are the best bet if temperatures are approaching the comfort limit of the bag.  Rectangular bags are fine when its warm, but you can spend a cold night in one if it is a little chilly.  A minority of people do use rectangular shaped bags, but I do not.

• Bigger, roomier bags (mostly rectangle shaped) are easier to roll over in.  In a tighter fitting mummy shaped bag, you turn from one side to the other by rolling the entire bag and your body together.  If its cold, you will briefly notice the cold on the side you were most recently lying on until the insulation re-lofts (i.e., the part you had been laying on fluffs back up).  It’s usually worth a few seconds of chill to get into a more comfortable sleeping position.
• Most bags come in men’s and women’s models.  It varies, but women’s bags may feature one or more of the following differences: shorter than men’s, have a little bit more insulation, be a bit narrower at the shoulder and wider at the hips, and may have a bit of extra insulation in places, for example in the footbox.  Some women may sleep warmer in a women’s bag, and some may not notice much difference.  Women tend to sleep colder than men, or at least that is someone’s working theory.  I don’t sleep like a man or a woman; I sleep like me.  The point is, if you’ve done much camping, you already know if you were warm or cold in the sleeping bag that you used.

Want to learn more? Check out our beginner backpacking series:

The links in this post to sleeping bag manufacturers are for your convenience. I have not been compensated for placing them here.