Part of the excitement of camping is getting wrapped up in your sleeping bag at the end of the day, and enjoying a night under the stars. The last thing you want is to be shivering until the early hours, not being able to keep warm. That’s why finding the right sleeping bag is essential for a comfortable night’s sleep. So before you head out on your next adventure, take a look at this article as we compare the different types of sleeping bags so you can decide which one is right for you.

How are sleeping bags rated?

To compare the warmth of different sleeping bags, you should look at their temperature ratings. This will make it much easier to choose the sleeping bag best suited to where and when you’re going to be using it. The rating of a sleeping bag specifies the lowest temperature at which the average person will remain warm inside. The three main types are:

  • Summer (0°C and above)
  • 3-Season (-10°C to 0°C)
  • Winter (-10°C and below)

Of course some people feel the cold more than others, but the above rating can be used as a general guide. When choosing your sleeping bag, you should select one with a rating just below the coldest conditions you expect to experience on your trip.

You may also find sleeping bags rated by season. Ratings start from season one for summer months, all the way up to five for extreme cold temperatures:

Season 1 - Summer

Ideal for warm summer nights, typically 5°C or above. Also good for festivals, and for indoor use such as sleepovers for kids.

Season 2 - Spring/Summer

For cooler evenings, temperatures from 0 to 5°C. Ideal for camping during school half-term holidays.

Season 3 - Autumn

For anywhere between 0 to -5°C, a cold night but no frost. Perfect for those who are braving camping in cooler weather and those who feel the cold when they sleep.

Season 4 - Autumn/Winter

Suited for the cold weather, for temperatures as low as -10°C, where there may also be frost or snow on the ground.

Season 5 - Winter

For expedition style camping and mountaineering, suitable for temperatures as low as -40°C. You’ll need a down sleeping bag to stay warm in these temperatures.

Down or synthetic sleeping bags?

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There are two key types of sleeping bag insulation to choose from: Down and synthetic. Down sleeping bags are made with the fine under feathers from ducks or geese, and synthetic sleeping bags are filled with man-made insulation.

Synthetic sleeping bags

Synthetic insulation is the most common type of insulation used in sleeping bags. A synthetic sleeping bag will perform better when wet compared to bags filled with down, and they are cheaper and easier to clean.

A big disadvantage of synthetic sleeping bags is that they do not retain heat like natural down. They are also much heavier and bulkier as they need more filling in order to work efficiently in a similar temperature range.


  • Cheaper than down
  • Retains insulation when damp
  • Easier to clean


  • Does not retain heat as well as down
  • Heavier & bulkier
  • Shorter life span

Down sleeping bags

Down sleeping bags are great in cold weather, as the loft of down creates thousands of tiny air pockets, making them more effective at trapping warm air and retaining heat. They’re also much lighter than synthetic bags and compress to a smaller size when packed, making them perfect for mountaineering.

The main disadvantage of down is that it absorbs moisture when damp. When it gets wet, the feathers lose their fluffiness and the heat insulating properties are lost. And as it takes a really long time to dry out, down sleeping bags are best suited to cold but dry conditions.


  • Good heat retention
  • Easier to compress & pack small
  • Lightweight (good warmth-to-weight ratio)
  • Suitable for cold & warm temperatures
  • Long lifespan if looked after


  • Loses heat insulating properties when wet
  • More expensive
  • Requires special cleaning
  • Takes a long time to dry out
  • Some cheap down sleeping bags may not use ethically harvested down

Whether you choose a synthetic or a down sleeping bag, it will need cleaning from time to time. Take a look at our guide to washing your sleeping bag to keep it fresh and clean, and to prolong the life of your bag.

What shape sleeping bag is right for me?

There are two main shapes of sleeping bag: The basic rectangle shape, and a mummy-style sleeping bag.

  • Rectangle sleeping bag: The basic rectangular shape sleeping bag has a zip around two sides. They’re spacious and can be fully opened and used as a duvet. And two bags can usually be zipped together to make a double sleeping bag. Though a rectangular-shaped sleeping bag will be less effective at retaining heat and are best for indoor use, caravanning and summer camping.
  • Mummy sleeping bag: This shape sleeping bag is more fitted than a rectangular bag. It tapers towards the feet and it is more effective at retaining heat. The hood of a mummy sleeping bag also helps keep the warmth in, and they often weigh less than rectangular bags. Most mummy bags will be single, but it is possible to buy right and left handed bags that can be zipped together to create a double bag.

Mummy-style bags are perfect for backpacking as they’re lightweight and better at retaining heat than rectangular bags. Your bag should feel snug without being too restrictive. You can also often find sleeping bags that come in different lengths for taller or shorter campers, or for different body shapes. And there are dedicated women’s, men’s and children’s versions too.

Need more help in choosing a sleeping bag for backpacking? Take a look at our handy backpacking guide.

What features should I look out for when choosing a sleeping bag?

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Not all sleeping bags are created equal, and there are certain features to look out for which will provide a more comfortable night’s sleep. The main things to look out for are a full-length zip as well as baffle construction. This means the sleeping bag is filled in sections, which stops the insulation moving around inside the bag and causing ‘cold spots’. Here are some of the other features to look out for when choosing a sleeping bag:

  • Left/right hand zips: You can buy sleeping bags with the zip opening on the right or the left hand side. For ease of opening, choose a bag with the zip on the left if you’re right handed (and vice versa).
  • Two-way zip: A sleeping bag with a two-way zip is useful for easy opening when you need ventilation. Zips can be full-length or half way, and they can also be used to create a double sleeping bag if you buy two of the same style and zip both together.
  • Zip baffle: Heat can be lost through the zipped area of a sleeping bag, so an insulated zip baffle (behind the zip) helps reduce heat loss.
  • Sleeping bag lining: Nylon and polyester are the most common materials used for lining sleeping bags. Flannel or cotton are also popular, although lightweight and breathable cotton traps moisture so isn’t ideal for damp conditions.
  • Outer fabric: The sleeping bag outer is often made of nylon-ripstop fabric as it’s highly durable. Dryloft shells are also commonly used due to their breathable and water-resistant properties.
  • Hood: As much of our body heat is lost through our head, a hood will help keep the heat in. A draw cord will also allow you to pull the hood tight against your face for extra warmth.
  • Inner pockets: These handy pockets are normally found near the top of the bag, perfect for keeping valuables safely tucked away.

Your sleeping bag will also come with a compression bag or stuff sack to make it easy to transport and store. Stuff sacks are often used on sleeping bags that are designed for camping trips or for when a larger pack size wouldn’t be too much of an issue. But when it comes to backpacking and trekking where space is limited, a compression bag with adjustable straps will ensure your sleeping bag is as small as possible when not in use.

7 Best Sleeping Bags of 2021

At Decathlon, we have sleeping bags to suit every type of camping, and every budget. We’ve included a budget sleeping bag, a lightweight sleeping bag, and our warmest sleeping bag so you can find the one that’s right for you. So here’s our rundown of the 7 best sleeping bags of 2021:

1. Most comfortable sleeping bag:

Arpenaz 0°C Cotton Sleeping Bag


This cotton sleeping bag has been developed for a comfortable night's sleep when camping in temperatures down to 0°C. It’s super cosy and it also turns into a duvet by simply unzipping it. It can be twinned to sleep two by joining it to a similar sleeping bag, and it comes complete with a 5-year warranty!

2. Best kids’ sleeping bag:

Forclaz 0/5°C Kids’ Sleeping Bag

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This sleeping bag is ideal for young camping enthusiasts! It’s warm and compact, making it the perfect companion for their first overnight camps away from home. It will keep them warm, even down to 0°C, and the two-way zip has been specially designed for little hands. Plus, it’s machine washable too so you can keep it clean and fresh, ready for their next camping adventure!

3. Best backpacking sleeping bag:

Trek 900 Feather Down Mummy Sleeping Bag 10°C


Designed in the French Alps, this RDS* certified down feather sleeping bag will keep you warm in temperatures down to 10°C. This excellent quality sleeping bag is warm, light and compact, and is mummy-shaped with an ergonomic hood. It’s also water-repellent to keep you dry, and to optimise its thermal performance.

4. Best lightweight sleeping bag:

Trek 500 Twinnable Mummy Sleeping Bag 15°C

This mummy style sleeping bag is part of our eco-design range, and has been designed so you can sleep comfortably at temperatures down to 15°C. It’s water-repellent, compact and lightweight, and can be twinned with other models from the Forclaz Trek 500 range to create a double.

5. Best mountaineering sleeping bag:

Makalu III Lightweight Sleeping Bag


This sleeping bag has been specially designed for walkers and mountaineers who need to be kept warm in sub-zero temperatures. The mummy shape is comfortable, the hood provides good coverage, and the down filling will keep you warm even at -20°C. It also has a 3D structure which prevents thermal bridges.

6. Best budget sleeping bag:

Arpenaz 15°C Sleeping Bag

This comfortable sleeping bag has a full zip for easy opening. It comes in two unisex colours, and will keep you warm in temperatures down to 15°C. It can be converted into a duvet, and it also comes with our 5-year warranty for peace of mind!

7. Best sleeping bag for all occasions:

Trek 500 Mummy Pairable Sleeping Bag 5°C


This all-round sleeping bag has been designed to keep you comfortable in temperatures down to 5°C. It’s extremely compact and light, and it has water-repellent fabric to optimise the thermal performance. It can also be twinned with other models from the Forclaz Trek 500 range.

Different situations call for different requirements from your sleeping bag. But in general, you’ll want it to be comfortable, suitable for the climate, and easy to store and transport. There are also a range of sleeping bags to suit different budgets, so at Decathlon, you’re sure to find one that’s right for you.