TL;DR  Contact us with any questions and we will be able to offer you expert advice on choosing the right sleeping bag for you.

Choosing the perfect sleeping bag is a tricky business. It's one of the most asked about topics in our shops and a real minefield of information for the uninitiated. Extreme temperature ratings, fill power, box wall construction; it can baffle even the experienced backpacker!

Choosing the right bag is also one of the most important decisions for the outdoor enthusiast. Getting a good night's sleep can make or break that much anticipated trip. Thankfully here at Craigdon we have bags of experience in this department so read on for our jargon busting, top tips to choosing the ideal sleeping bag for your next big adventure.


Where, when, how?

The first thing to think about when looking for a new sleeping bag is the intended usage. This might seem obvious but many sleeping bags come with a “season” rating which can catch you out. You have to ask yourself; who’s seasons are we talking about here? For a Cornish beach camping trip in July, a 1 Season bag will be perfect. Sleeping out on a Scottish mountain top at the same time of year will have different requirements and a 3 season bag will likely be more suitable. Do some research on average nighttime temperatures for your location and if in doubt err on the side of extra warmth. It’s a lot easier to cool down by undoing zips etc than it is to get warmed up in something too thin.

How far will this sleeping bag be carried? If it is for car camping, festivals and the like; you don’t need to worry too much about size and weight. For multi-day backpacking, choosing a very light and compact sleeping bag is one of the best ways to lighten your load. A lighter backpack = maximum enjoyment. It also leaves a lot more room for snacks :D

Nice and cozy in the bothy with Mountain Equipment sleeping bags.

Temperature ratings

The vast majority of sleeping bags on the market and all of the models on sale at are tested using the standardized methods EN13537 or ISO23537. If you really want to geek out on this topic then Mountain Equipment has an excellent explanation of these tests here.

To put it simply; the EN/ISO tests produce three different temperature ratings:

Comfort Rating:  This rating is defined as a temperature at which a ‘standard female’ in a relaxed posture will feel comfortable inside a Sleeping Bag. If you are female or a cold-sleeper, this is the temperature rating that is most relevant to you.

Limit Rating:  This rating is defined as a temperature at which a ‘standard male’ in a curled-up posture can sleep inside the Sleeping Bag without waking for an eight hour period. If you are a male, or are not a ‘cold sleeper’, then this rating is most relevant to you. This is also the rating which is advertised most widely for most sleeping bags.

Extreme Rating:  This rating indicates the minimum temperature at which a ‘standard female’ can remain for a total of six hours before risking the chance of hypothermia and damage to health. Generally this rating should be treated as a guide to how the Sleeping Bag performs under extreme emergency situations, and should not be considered a factor in making a purchase.

Temperature ratings are a good guide for comparing sleeping bags but they are highly subjective in how they relate to individual experience. Differences between male and female physiology mean that generally, but not always, women will feel the cold more acutely than men. If you would like to know more about this then you can read about it here. If you are a cold sleeper then you will likely know about it and should take this into account when looking at temperature ratings.

It is also possible to boost the warmth level of any sleeping bag with a good sleeping bag liner. The SEA TO SUMMIT Thermolite Reactor Sleeping Bag Liner is an excellent example of this which is capable of boosting the heat levels by up to 8 degrees celsius!

Synthetic vs Down

Let’s start with the pros and cons of down filled sleeping bags here since it is the logical choice for serious outdoors folk. Duck or goose down has a far higher warmth to weight ratio than other available insulation. It is highly compressible, breathable and will last for many years/decades if cared for correctly. If you carry your sleeping kit on your back or bike for any significant amount of time then it really is the superior choice. It is more expensive so should be viewed as an investment. The MOUNTAIN EQUIPMENT Helium 400 is a great example of a super versatile, high quality down sleeping bag for all sorts of outdoor activities.

Down does not like to get wet however. The feathers will clump together when damp and lose their insulating properties needing to be thoroughly dried out before being used again. New hydrophobic down products have come onto the market in recent years which have improved things somewhat but we would always recommend keeping your down sleeping bag in a good quality drybag. In the real world, if you camp out in a tent, it’s not that hard to keep your sleeping bag warm and dry. Weight and space savings make owning a down bag a no-brainer.

Synthetic fill sleeping bags are heavier and bulkier than their down counterparts but generally a lot less expensive. There are plenty of good synthetic bags available for under £50 and they are ideal for budget conscious trekkers or for those who don’t care about pack size and weight. That being said, not all synthetic sleeping bags are created equally. Higher quality synthetic bags are much lighter and pack down far smaller than cheaper ones. Synthetic sleeping bags are also far easier to wash and they don’t mind getting wet which could be a major advantage in some situations. We normally recommend a good quality synthetic sleeping bag like the VANGO Microlite 200 for Duke of Edinburgh expeditions and Scout camps.


These 2 sleeping bags from Vango have the same temperature rating. Can you guess which one is down and which one is synthetic?


This is often overlooked but it’s really important that your sleeping bag fits you well. Especially if you will be camping out during the colder months. A close fitting bag will have greater thermal efficiency. For this reason most of the sleeping bags you see on are mummy style. Rectangular sleeping bags are much more spacious but have to have a lot more insulation to achieve the same level of warmth. For this reason they are often bulky and best suited to car-camping, festivals and campervans. The VANGO Era Grande is a fantastic example of a cozy, roomy, rectangular sleeping bag for those occasions where you don’t need to carry your sleeping kit very far.

For every other application a mummy style sleeping bag will likely be best. If the bag is too tight it will feel restrictive and uncomfortable. You also risk compressing the down insulation, compromising its thermal performance. If there is too much volume then the air inside will circulate and it will take much longer to heat up. The Mountain Equipment Helium range of sleeping bags is a perennial favorite here at They are quite a close fit which works great for most people but is a little tight for some. This year we are stocking their new Helium GT range which have the same great technical features but with a much roomier fit. It’s great to see a super lightweight option for bigger people or campers who just want a bit more room.

It’s important to note the maximum user height because if you are over 185cm (6’1ish) you may wish to opt for a longer length sleeping bag. Mountain Equipment, for example, make most of their technical sleeping bags in a long length option for tall people. Danish brand Robens are also extra long and roomy even in their regular length. The ROBENS Gully 300 is a fantastic, lightweight option for bigger folks.


The huge price range between the very cheapest synthetic sleeping bags and expedition specced ones is as much to do with the internal construction as it is to do with the materials themselves. The most basic type of construction is “stitched through”. This is used in both synthetic and down sleeping bags and is very cost effective. It does leave uninsulated “cold spots” along the stitch lines however so is generally not used in sleeping bags designed for use outside of Summer. Overlapping shingles of synthetic insulation resolves this and is something you should look out for if you are looking for a good synthetic sleeping bag.


When it comes to down sleeping bags, there’s probably more going on beneath the surface than you think. Controlling the movement of the loose down is the name of the game here and there are many types of baffle construction to achieve this. The best bags will use different types and sizes of baffles in different parts of the sleeping bag. For example, smaller baffles with a higher density of down may be used in areas which may be compressed such as the base and the foot box. The baffles on top top of the bag will typically be bigger with a lower density of down to allow for greater loft.

There are lots of other features that, while adding cost, will also increase warmth and comfort. Zip and neck/shoulder baffles help to prevent drafts and keep warmth in. A properly shaped foot box will help keep those tired feet comfortable. A well fitting hood is invaluable in cold conditions. A high quality, water resistant outer fabric will be invaluable for longer trips where condensation could be an issue and when drying out a sleeping bag could be difficult.

A high Alpine bivvy with Mountain Equipment Helium sleeping bags

It’s a complicated product area so we would encourage you to get in touch with us if you need specific advice or just can’t decide what sleeping bag to choose. The team here has lots and lots of experience using all sorts of different sleeping bags, in all sorts of places, in all sorts of conditions, at all times of the year!

If you are just starting out then you should know that getting kitted out for overnight missions opens up a whole new world of adventurous  possibilities. Go for it!

We very much look forward to hearing from you :)