How to choose a sleeping bag

How you sleep makes or breaks a good adventure. Waking up warm and rested means you start the day with energy and a smile on your face. On the other hand, tossing and turning and shivering your way through the night won’t just result in a moody camper; you’re also more likely to get ill and/or make silly mistakes. The difference between a good and bad night’s sleep largely boils down to whether you’re using the right sleeping bag. Before you make your final decision, ask yourself these questions.

When will you use it?

Sleeping bags are all about insulation. They don’t actually provide heat – it’s your body that does that. A sleeping bag’s job is to retain the heat you produce. So all sleeping bags have temperature limits. These limits should be a guide. You should also take into account whether you’re a generally ‘warm’ or ‘cold’ person. And we suggest erring on the side of caution. You always want to give yourself a margin of error. Oh, and women generally ‘feel’ colder than men, so ladies will want to choose a sleeping bags that can cope with colder temperatures.

If, on the other hand, the temperature is warmer than expected, you can unzip the sleeping bag and stick out a foot, leg or arm. This will help cool your entire body. Some of our sleeping bags have zips that extend around the feet, allow you to cool off more easily when the temperature rises.

Standardised sleeping bag temperature limits are as follows

Upper limit

The temperature at which the average man can sleep without sweating too much. It’s measured with the hood and zippers open and the arms on the outside of the sleeping bag.

Comfort limit

The temperature at which the average woman can sleep comfortably in a relaxed position.

Lower limit

The temperature at which the average man can sleep eight hours without waking.

Extreme limit

The lowest temperature at which the average woman can survive with the sleeping bag (although this doesn’t mean experience will be a comfortable one).

Aside from your gender, there are few other things you should take into account. The older you are, the more susceptible to cold temperatures. So go for a lower extreme temperature limit. You should also factor in your height and body fat percentage. You want your sleeping bag to be cosy, but not too tight. This will restrict its insulating power. And if you have a less body fat, think about getting a more insulating sleeping bag.

How will you use it?

Are you planning on filling your backpack with all your gear and heading into the wilderness or travelling around the world? Maybe you want something for occasional use that you don’t have to carry that far?

The size (compressibility) and weight of your sleeping bag are really important, particularly if you’re planning on carrying it over long distances or need to find space for it in your backpack.

Size and weight are directly related to the filling of the sleeping bag. Generally, sleeping bags are filled either with down feathers or with a synthetic material, that looks pretty similar to down but it’s actually man-made.


Usually from geese, is an outstanding natural insulator. When you look at a down feather under a microscope it looks like a tree. The stem, the part that attaches to the bird’s skin, is the trunk. Then a plethora of small fibres branch out into ever-smaller fibrils. This loose structure traps air in the spaces between the fibres and it’s the air that insulates against heat loss. And because it’s just air, down is also really compressible. This is ideal for sleeping bags that need to be stuffed into backpacks.

Down sleeping bags, therefore, are ideal for trekking and travelling. They are light, offering outstanding warmth for their weight and can be compressed down to often mindbogglingly small packages.

However, down isn’t perfect. As soon as it gets wet it loses a lot of its insulating capacity and becomes heavier. So down sleeping bags aren’t ideal in damp conditions. Plus, as they’re more expensive than synthetic sleeping bags if you’re just an occasional camper, a synthetic sleeping bag is your best bet.

The structure of synthetic insulation mimics that of natural down. Therefore it’s also about trapping heat using air pockets. However, unlike down is can’t be squashed down to next-to-nothing. It’s a little bulkier and heavier as a result. On the plus side, synthetic insulation doesn’t lose its insulating power when it gets wet. It’s also way easier to take care of – you can put it in the washing machine, for example. All this makes it ideal for beach camping and camping trips that don’t involve tight spaces or the game of trying to fit all your gear in a 65L backpack.

You can read more about the difference between down and synthetic insulation here. Note that our down is 100% traceable, does not involve live plucking and is a by-product of the food industry.

How do you sleep?

We’ve customised some of sleeping bags to the way you sleep. We have “Move In Bag” and “Move With Bag” versions. The names are pretty self-explanatory. With the former you wriggle around inside the sleeping bag while you sleep. With the latter you roll around inside the tent, but aren’t so fidgety inside the sleeping bag. So how do they differ?

A move in bag

Has 60% of its down on the topside of the sleeping bags, more over the torso than the legs. This is to keep the main insulating power on top of the sleeping bag, so no matter how much you move inside the bag, your body heat will always be retained. It’s also a little wider, allowing you to more easily more around inside the sleeping bag.

A move with bag

Is a little narrower, making it easier to take with you as you move. The down is also evenly spread between the core area on the top and underside of the sleeping bag. So no matter how much you roll around, your body heat will be retained.

Editor’s favourites

The trekker: Singi three seasons

Filled with 90% goose down and 10% feathers this sleeping bag is really compressible. And 700CUIN fill power offers a comfort temperatures of -2°C.

The beach camper: Abisko two seasons

Filled with synthetic insulation this sleeping bag warms even when it’s damp. The tapered “mummy” shape means it doesn’t take up much space either.

The person that’s always cold: Fjällräven Polar -20

Designed specifically for polar conditions, this sleeping bag packs a full 800CUIN of insulating power and has a comfort temperature for women of -12°C.

The person that’s always warm: Move with bag  

A zip that extends right round the feet gives plenty of options for cooling off. Stick out your feet or un-zip the sleeping bag complete and use as a cover instead.


This site is using cookies for a better shopping experience. By using this website, you agree to our data protection policy and cookie policy. Please read our data protection statement for more information.