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What sleeping bag do I need for camping in the UK?
When you first delve into the world of sleeping bags you’ll see that many are talked about as being two-, three- or four-season bags. As you’d imagine, four-season bags are the preserve of brave souls who intend to camp in winter on frozen ground. A three-season sleeping bag (spring, summer, autumn) will serve most purposes. A two-season (spring/summer) is fine for those only intending to camp when the sun shines.
The best fillings for sleeping bags are synthetic fabrics or down (usually eider, goose or duck feathers). Down has a fantastic warmth-to-weight ratio, is lighter and packs down smaller, but if it gets wet (and it has not been treated with a waterproof agent by the manufacturer) it is less effective at keeping you warm. The feathers stick together and stop trapping warm air. Synthetic fabric will still keep you warm even if it gets wet, though the payoff is that it’s usually bulkier to pack and heavier.
Sleeping bags are commonly rated by the minimum temperatures they can cope with: the warmer the bag, the lower the temperature. There’s a difference between the ‘comfort’, ‘limit’ and ‘extreme’ temperature ratings, though, which I explain at the bottom of this feature along with a guide to sleeping bag sizes and how best to care for them between adventures.
What are the warmest sleeping bags?
While the season rating (two-, three- or four-season, see above) gives a good idea of how warm it is, you can also check the temperature rating on the bag. There are three that can be used: Comfort, Limit and Extreme.
You’ll see impressively low temperatures for ‘Extreme’ but this just means it’s the absolute coldest condition under which this bag will save you from getting hypothermia.
The Comfort temperature rating is more useful. It shows you how cold the outside temperature can be while still allowing you to sleep in warmth and comfort. The average night temperatures for spring, summer and early autumn are around 4°C and above, so you’d certainly want something rated to 4°C or below.
Some people – usually men – are hot sleepers and are comfortable at lower temperatures. This is given as the Limit temperature rating. (That is, the lower limit of comfortable sleep.)
You will usually see these ratings preceded by the letters EN or ISO. These are the two recognised and independently verified industry standards, with EN used more by European manufacturers and ISO by those made in the USA. Some manufacturers don’t use either and simply do their own rating.
What does GSM mean?
This is grams per square metre. It’s used to rate how much filling a synthetic sleeping bag contains and a good number is about 300+.
Down sleeping bags are often rated for ‘fill power’ instead: the higher the number, the warmer the bag. 500 is good. Anything higher is excellent.
How do you know what size sleeping bag to get?
All the sleeping bags above are R (regular) but bags also come in S (short) or L (long). When looking at the advertised length of bag, make sure that the number refers to the ‘fits’ length (that is, the maximum height of the person that can fit inside it) rather than just the length of the entire bag.
It’s worth considering a women’s fit bag – and not just if you are a woman. Women’s bags tend to offer extra warmth around the feet, as well as a wider fit around the hips and narrower fit around the shoulders, so it’s worth considering if this sounds like you.
How to store a sleeping bag
Most high-quality sleeping bags come with two sacks: a smaller compression sack with tension straps to squeeze out all the air, so that it packs down as small as possible, and a larger bag for storing it between trips. If you store sleeping bags in their compression sacks for months at a time, you will damage the filling and it won’t loft (fluff up to trap warm air) properly, making it less effective at keeping you cosy when you camp.
After every trip, air dry it to allow any moisture to escape. Then store inside the supplied sack, or a large pillowcase if it doesn’t come with one. Never use non-breathable plastic bags. You must allow air to circulate. Keep it in your wardrobe, rather than in your attic or basement.
- Phoebe Smith is an adventurer, author and host of the Wander Woman travel podcast
