Choosing a sleeping bag is an essential and important decision. Your sleeping bag determines the quality of your sleep, your comfort, your recovery, and it also gives you the mental benefit of proper relaxation in a cosy cocoon. A good sleeping bag is therefore important for any hiker, whether on long-distance routes or short multi-day trips. Let's explore 6 essential criteria for choosing a sleeping bag suited to your needs and your hikes.
The comfort temperature
The first selection criterion when choosing a sleeping bag is temperature. Among the temperatures listed, the one to focus on is the comfort temperature. This is generally the figure highlighted by the manufacturer or retailer. It indicates the temperature down to which you will be comfortable in the bag without feeling cold.
Do not confuse it with the lower limit temperature, which indicates the temperature at which you need to curl into a foetal position to avoid feeling cold. Finally, the extreme temperature is the point at which you will feel cold in your bag even in that position. Below this temperature, the risk of hypothermia is real and it is strongly advised against spending a full night in such conditions.
Key criteria for choosing the right comfort temperature for your sleeping bag
To choose a bag with the right comfort temperature, you need to consider the geographical area of your hikes and the altitudes where you will be sleeping. Also think about your bivvy conditions (open air, tent, mountain hut), the season, and of course the weather conditions (not just temperature, but also the risk of bad weather).
Bear in mind that even in temperate zones in summer, temperatures can drop significantly at night once you are at altitude. Humidity and wind are also important factors. Cold sensitivity varies from person to person depending on build and fitness level. If you feel the cold easily, consider choosing a bag with a comfort temperature rating slightly lower than the temperatures you expect to face. Also keep in mind that you will feel colder when tired and when you haven't eaten.
For a summer night, a sleeping bag with a comfort temperature of +5°C is sufficient. In mid-season, a temperature of 0°C is recommended. For winter and cold nights, opt for a comfort temperature of at least -5°C.
The temperatures stated by manufacturers are reliable and comply with European standard EN13537. This standard has the advantage of making sleeping bags from different brands comparable on this criterion.
And if you use your sleeping bag in variable temperature conditions, you can add a silk sleeping bag liner or a fleece mummy liner to gain a few extra degrees of warmth.
Weight
For fully self-sufficient hiking, weight is an important factor. For other types of hiking, weight still matters but is slightly less critical. Down sleeping bags offer the best weight-to-temperature ratio, but there are no miracles: you won't find an ultra-light sleeping bag with a low comfort temperature rating. Weight is therefore important but often a matter of compromise when choosing a sleeping bag suited to your needs.
Choosing the fill for your sleeping bag
A synthetic sleeping bag is often heavier than a down equivalent at the same temperature rating. It is also less compressible. However, it handles moisture better. It is therefore particularly well suited if your bag is likely to be exposed to bad weather, or for example if you sleep under the open sky in a damp area. And finally, a notable advantage: synthetic bags are also more affordable than down bags.
A down sleeping bag is lightweight, compressible, highly insulating and breathable. However, it loses its insulating power when wet. The downside of down feathers is that they tend to clump together with moisture, reducing the quality of insulation and thermal comfort. Moreover, down fill can, over time, have the unfortunate tendency to gather in clumps in certain areas of the sleeping bag, reducing the consistency of comfort and insulation.
Choosing a sleeping bag with synthetic fill is therefore a good compromise for value for money and for less demanding expeditions in terms of pack weight.
Sleeping bag shape
Mummy sleeping bags have an anatomical shape: they follow the contours of your body, optimising thermal protection. They are also lighter and less bulky than rectangular bags. That said, they can feel a little restrictive, and some people prefer the roominess of a rectangular bag.
Rectangular sleeping bags are more comfortable as they are roomier around the feet. However, with comparable fill, they offer less effective thermal protection as they contain more air. On the plus side, they are easier to get in and out of and simpler to use.
The closure system
This element is important to prevent cold air from entering the bag and warm air from escaping. There are various closure types, sometimes with drawcord systems on the hood for mummy bags. Above all, pay close attention to the quality of the zip and the finish. You will use this zip a great many times, and you certainly don't want to get stuck inside. So carefully avoid models where the zip feels flimsy or difficult to operate.
Volume when compressed
This is an important criterion if you don't want to be burdened with an overly bulky bag. Down bags compress better and are therefore generally less bulky than synthetic bags. That said, it is not the most important selection criterion, but it can help you choose between otherwise equivalent products.
The perfect sleeping bag doesn't exist. You need to choose a sleeping bag suited to your needs and the type of hikes you do. If you mainly go on multi-day hikes without needing full self-sufficiency, you don't need an ultra-light, highly compressed bag. Prioritise comfort and insulating power instead. On the other hand, for long expeditions, packability and weight become more important factors. You can also have several sleeping bags suited to different conditions and types of hike. One thing is certain: choose a quality sleeping bag — it's an essential companion on your treks and multi-day hikes.
Check out our article: How to care for and wash your sleeping bag.
