all you need to pick the right tool for the job

Seasons, warmth ratings, insulation type, shape. If you don’t know exactly what you’re looking for, choosing a new sleeping bag can be an overwhelming task. But fear not, we’re here to talk you through the steps to choosing the right sleeping bag for you and the considerations you’ll need to make the right decisions. Whether that’s for a high altitude mountaineering expedition or perhaps a trek across the dry and exposed desert with its wild temperature ranges or the humid depths of the jungle.

As with all your outdoor kit, the first consideration as you look to choose a new sleeping bag has to be how and where you’re going to use it. What kind of temperatures are you expecting? How will you be carrying it? What’s the likelihood of it getting wet? It’s all about choosing the right tool for the right job.

Warmth Rating

So the obvious place to start then is going to be what temperature range your sleeping bag can cope with and also how your own sleeping routines and preferences relate to that. Are you going to be camping in winter, at altitude or in generally harsh cold conditions? Do you tend to run warm at night or particularly cold?

Generally a sleeping bag will be rated by a season. Either 1, 2, 3, 3+, 4 and 4+ season. The higher the number, the colder conditions you can expect to be comfortable in which can offer a broad understanding of what kind of temperatures you can expect to comfortably use the sleeping bag in. In a 1 season bag for example you’d expect only to be comfortable in the warmest of summer evenings, with 4 offer warmth in the depths of winter with 4+ accounting for high altitude and expedition bags.

Each sleeping bag will then be marked with several temperatures to suggest their intended temperature ranges. Comfort, comfort limit and extreme. These are pretty self-explanatory so you of course want to be aiming for a sleeping bag that’s comfort range is going to match with the temperatures you’re expecting. It’s better to err on the side of caution with this. You’ll want to be the warmer side of comfort, particularly after a long day of physical output on the hills and if you end up a bit warm, you can always unzip the bag slightly to allow some air flow.

Warmth to Weight

If you’re car camping, at a festival or perhaps just kipping on your mate’s floor then this won’t be so relevant, but during any sort of expedition, you’re likely to be to carrying your sleeping bag and you’ll probably want to minimise your kit size and weight. This is when warmth to weight ratio is really key. What we mean by this is that you maximise the warmth you’re getting from your bag in relation to its weight and pack size. This becomes particularly important when you’re backpacking for several days, soon resenting every wasted gram and litre of volume in your pack.

Down vs Synthetic

While there are more pros and cons to consider for each type, typically the key thing to note here is down’s impressive warmth to weight ratio. Down is incredibly light and compressible meaning it’s very well suited to self-supported journeys where pack size and weight is at a premium.

Synthetic insulated bags will be slightly heavier and larger in relation to their warmth rating. The two can be as warm as each other, the key thing to remember is for synthetic bags you’ll need more insulation to reach the same warmth meaning you’ll add weight and size. The key benefits to synthetic bags is that they retain their warmth in wet conditions and are much easier to wash while you’ll have to make sure to keep your down bag dry and clean.


More technical bags intended for colder use will generally be shaped to be narrower at the head and the legs to follow the natural contours of the body, remaining close enough to your body for maximum heat retention. It also means there’s less overall fabric meaning smaller pack size and weight.

You can usually find sleeping bags sized as regular or long which is worth considering again to minimise dead space but ensure you have enough room for a comfortable night’s sleep. You can also often find women specific sleeping bags, shaped to better suit the female anatomy with narrower shoulders, wider hips, and extra insulation in the upper body and foot box. Wide or rectangle sleeping bags are aimed at comfort over performance.


Finally, you’ll want to have a think about some of the key features you might be keen for your new sleeping bag to include. Modern sleeping bags come with a whole range of different hood types with different functions in mind to think about once you’ve nailed the temperature range, shape and material.

You might opt for magnetic fastening systems, a two way zip or anti-draft neck baffles for added comfort and warmth in a bag for colder conditions. You might also look for a stash pocket to keep your valuables safe which might be particularly useful if you’re sleeping out or using a bivvy bag rather than a tent. These additional features should be considered only as a bonus to the key features of the bag.

If you’re booked on to a Secret Compass expedition and aren’t too sure what you need or want to discuss the options, don’t hesitate to get in touch. We love to chat kit!