A good sleeping bag is the difference between a good night’s sleep after a day of fun in the sun, hiking or any other crazy hobby that you can dream up, and a horrible cold night dreaming of being at home in your bed. If there is anything that can ruin a holiday faster, it’s a bad night’s sleep.
The aim of a sleeping bag is to trap the warm air, heated by your body inside the sleeping bag, and the cold air outside. In emergency situations the right sleeping bag is the difference between life and death.
Remember that you are the heat source in a sleeping bag, the sleeping bag is just there to keep the heat trapped around your body. Ideally when you go to sleep you should be warm, dry and well fed. Go to the toilet before getting into your bag. Once you get out most of that heat will be lost. Wear light but warm clothes like a base layer and socks and a knitted hat if you think you might be cold. Draping your jacket over you, or adding more insulation underneath you, will help if you still feel cold.
Buying a sleeping bag seems to need a degree in sleeping bag labels. Follow our quick guide to what the labels mean, and what to look for when buying your new sleeping bag.
1 and 2 season
1 and 2 season sleeping bags are great for use indoors or camping on warm summer’s evenings. Normally the lower limit is about 5 degrees at the coldest.
3 season sleeping bags, on the other hand, are designed for when the nights get a little chillier in spring and autumn.
4 season sleeping bags should keep you toasty warm all year round. But always read the comfort temperature range, as some bags even within the same season have different ranges.
Recently a European wide system for measuring and assessing the warmth and comfort of a sleeping bag came into play. This covers the comfort range and the extremes that a sleeping bag can handle. The testing is done using a computer-controlled dummy placed in a carefully controlled climate chamber and monitored to see how the sleeping bag controls the temperature around the dummy.
It is worth noting that women need a comfort level approximately 5 degrees warmer than men. This is a general guide line and there are a large number of other factors to consider.
The upper and lower limits of a sleeping bag
These are the practical limits, you might not be comfortable, but bag should keep you warm/cool enough to sleep without extreme discomfort. At the upper end the assumption is that you’d have the bag unzipped and the hood down if you have one. The extreme lower limit is what you will be able to survive in. Frost bite might still occur but you can survive.
This is the temperature range that you should be able to be comfortable at. It’s based on the average comfort level of 25 year old man or woman. Ideally, a sleeping bag buyer will aim for the widest range so that the bag is as comfortable as possible in the widest range of conditions.
Normally sleeping bags have two ratings, so -4/1 would mean that the bag will be comfortable for men at -4 degrees and women at 1 degree. Whilst it may seem simplest to buy the warmest bag possible this presents issues. For example, a sleeping bag designed for camping in harsh conditions will be too warm to sleep in during the summer. Moreover, the extra weight and bulk will make it more difficult to carry around.
How do you handle the cold?
Some people start to shiver long before others. If you’re that person who’s putting on a jumper whilst everyone else is still in t-shirts, then remove about 5°C from the lower comfort temperature. For example, a bag with a comfort rating of 0°C might be better than a 5°C rating, if you’re particularly susceptible to the cold.
The factors that influence how cold we feel include:
Age brings wisdom and the tendency to feel the cold more than younger people, remember the bags are tested by a assumed 25 year old. If you’re older and know you start shivering before anyone else, it’s worth adding 5 degrees to those comfort ratings.
Women feel the cold more than men. This is scientific fact, not just a stupid statement around the camp fire by the lads bragging, sorry ladies.
If you’re a frequent camper, you get used to the cold and the warmth. Occasional campers feel the temperatures more than regular campers. If it’s your first time camping, it’s worth buying the best bag you can afford.
Being hungry and thirsty can upset your body’s natural systems. This will cause you to feel the cold more as your body stays warm by burning calories. Now think about the impact after a day of physical exertion that saps away all your bodily fuel.
It’s a myth that alcohol warms you up. In fact, it can make things worse. Alcohol makes the blood vessels near the surface of your skin dilate, hence why drunk people become red-faced. This blood flowing to the surface of the skin means you lose heat faster and your core body temperature drops.
Low body fat
The larger you are, the less you feel the cold. This even the case if you are more muscular as more muscles means your body burns more calories. Burning those calories produces more body heat. Fat is a good insulator.
- Exposure to the wind
- Moisture in the air
- Not being insulated from the ground
- High altitudes
If in doubt, always buy a bag with a comfort level lower than you expect to be sleeping in. So if you think 10 degrees is going to be the lowest temperature, go for 5 degree. You can always sleep with the zip open and the hood down if it becomes too warm.
Down vs synthetic insulation
This may seem like an argument between people who can afford expensive down sleeping bags and equally expensive synthetic technical sleeping bags. But the down vs. synthetic fibres debate is a bit more than that.
Down is a layer of fine feathers found under the tougher exterior feathers of birds. Most down comes from water fowl, specifically geese and ducks. Down is a great thermal insulator and padding, used in jackets, bedding, pillows and sleeping bags.
Various types of down exist. Goose down from older bird, generally from Eastern Europe is the most expensive, whilst duck down from young birds is the cheapest.
When down is compressed, the fibres create small air pockets to trap air in the filling of the sleeping bag. These small pockets of air trap heat. The proof is in birds themselves – even in the depths of winter they do fine with their feathers to keep them warm.
Pros of down insulation
- Down insulation is extremely effective at keeping you warm. As a rule of thumb, down gives twice the insulation for the same weight of synthetic fibres.
- It’s also very durable. Down tends to last longer than synthetic fibres with good maintenance. Some sources claim it is capable of lasting two to three times longer.
Cons of down insulation
- Down is a really poor performer once it gets wet, and takes ages to get dry. If your sleeping bag is at any risk of getting wet, then down is the wrong choice. Having said that, there are very few situations where we plan to endure wet sleeping conditions during our outdoor excursions.
- Short term down is a lot more expensive, but when you factor in the long term savings down works out to be cheaper, if you take care of the sleeping bag.
Synthetic insulation is designed to replicate natural down. Made from pure polyfibres, synthetic fibres are general considered to be the cheaper option when it comes to sleeping bags.
Both types of fillings have a price range and various qualities, cheap down vs. expensive synthetics may not be a fair comparison.
Pros of synthetic insulation
- Synthetics will perform quite well even when wet (up to 50% as effectively as dry) and they dry a lot quicker than down.
- If you tend to damage sleeping bags, or only plan to use it for a short period, synthetics are the cost-effective choice.
- Some people are allergic to dust mites and their faeces. Synthetic insulation is hypoallergenic and will not irritate allergies if kept clean.
Cons of synthetic insulation
- To provide the same amount of warmth synthetics can be twice as heavy, and if you’re carrying it around all day ever gram of weight will count.
- Synthetic won’t last as long as down. But they do require less care, and can be discarded, replaced and still be cost effective.
Down insulation would seem to be the clear winner, but there are a number of reasons that synthetic fillings are a valid choice:
- When camping in potentially wet conditions
- If the bag is only to be used for a short amount of time
- When working to the constraints of a tight budget
- If you know you won’t have the time to wash and care for your sleeping bag
The shape and size of a sleeping bag
Weight is only really a concern if you have to carry your bag for long distances. Backpackers, or even cyclists or kayakers, will likely be doing this. If you do have to carry your bag then every gram counts.
Packed size is important if you need to fit your bag inside a backpack cycle pannier or kayak hatch. Often you can strap your sleeping bag on the outside of other bags with your tent. Generally it’s possible to compress a sleeping bag more than the packed size states. But compressing your sleeping bag flattens the fibres and reduces the insulation’s effectiveness.
You might think a sleeping bag is just a rectangle that you can climb into, but the shape can really influence how comfortable you are. The more space inside the sleeping, the more space you need to heat, but too tight and you feel confined.
This is the most popular shape. It’s basic and compact making it great for indoor use, or on very mild summer camping trips. But the extra room means extra heating, and lack of hood and open neck means that heat escapes easily.
Double sleeping bags are sleeping bags that are suitable for two people to use. They are normally rectangular bags with opposite zips, i.e. one left handed and one right hand zip. Though, a double sleeping can still be too restrictive for two people.
Another common design, the mummy sleeping bag is tailored to be as snug as possible. It narrows at the feet, and tapers up to be wider through the hips and the shoulders. A hood with a draw string around the face will keep heat loss around your head to a minimum and the space that you need to heat is at a minimum.
Generally these bags take up less space when packed and weigh less, if you plan on camping in anything but the mildest weather, then you’ll need a mummy sleeping bag.
The hood on a mummy sleeping bag should fit to your head with a series of panels designed to curve around and cover as much of your head as possible.
Draft collars are at the base of the hood, allowing you to pull the collar tight over your shoulders and leave the hood to cover your neck. These again normally have drawstrings to tighten them.
As well as being smaller and normally more brightly coloured, there are plenty of technical sleeping bags for children. Price can be a consideration with children’s bags as they might outgrow them rapidly, but you also don’t want to put them off camping by buying a cheaper sleeping bag and leaving them cold and uncomfortable of a night.
Sleeping bag pockets
Some sleeping bags have inner pockets for a small amount of valuables, such as wallets, purses and mobile phones. Though, using them runs the risk of rolling onto your belongings and possibly damaging them.
You may also find pockets located in the hood area. This allows you to put something in the hood to use as a pillow. Normally this is in sleeping bags where weight is an issue and this pocket is often used for clothes. The extra weight and space taken up by a dedicated pillow isn’t worth it on a long hike.
The lining and outer shell of a sleeping bag
If the sleeping bag warmth comes from the filling, then the outer shell and the lining are also important. The liner absorbs the interior sweat and moisture that can leave users feeling clammy and uncomfortable. Some liners have a reflective liner to reflect heat back towards your body. As these tend to reduce breathability they are better on sleeping bags designed for colder temperatures.
The outer shell should be treated to repel dirt and water. The outer shell is commonly made from rip stop nylon while the inner liner is brushed polyester.
Right or left handed sleeping bags?
There is nothing worse than waking up in the morning and not being able to unzip your sleeping bag to go to the toilet. It’s not that it’s disappeared – it’s that we use a dominant hand, by nature, but we don’t consider how this effects where the sleeping bag zipper is located. The hand nearest the zip has no leverage because it is too close, so the zipper should be on the side away from your dominant hand.
For instance, if you’re right handed you need a left zipped sleeping bag and vice-versa. Most sleeping bags have the zip on the left side to make it easier for the right-handed population.
Some sleeping bags have zips that go all the way around and across the bottom. This has two advantages:
- The first being you can unzip the bag all the way round and lay it flat for drying out or spreading over the top of a bed or similar.
- The second being that you can unzip the bottom if you need to walk around and are too comfy to get out of your sleeping bag.
Zips can be single or double, a double zip can be opened from either end, great if you need extra ventilation.
The construction of the sleeping bag
Sleeping bags are constructed by creating a series of internal baffles, these are the sections created between the inner and outer lining. These baffles mean the insulation is distributed evenly across the sleeping bag.
This simple method is where the shell and lining are stitched together to create a line of baffles. This system is only used on one season sleeping bags as it only allows a small area for the down or synthetic fibre to lift in.
A simple method with vertical side walls to keep the insulation in place. The clue in in the name, in that each of these baffles is like a box. It does not hold the insulation down as effectively as trapezoidal or shingle construction, leading to the greater possibility of cold spots.
This is a more complex method in which each baffle wall is inclined at an angle to form a series of ‘V’ shapes. This method of construction is used to obtain the greatest number of baffles in a single layer construction.
The popular ‘in between’ design that provides more baffles than a box wall construction but less than a V construction.
Think of this as the more advanced version of trapezoidal baffle construction. A shingle-constructed sleeping bag offers excellent cushioning, heat retention and loft. However, it is complex and expensive to manufacture.
Two-layer offset stitch
a system with two box wall layers with seams in the middle that are sewn on top of each other. The baffle walls are offset relative to each other, creating a similar appearance to that of a brick wall. It provides a high level of insulation, required for sleeping bags that are designed to cope with colder temperatures.
Caring for your sleeping bag
When arriving at camp, it’s worth getting your sleeping bag out a few hours before you go to bed if possible. Shake out the bag to allow the insulation to expand and recover its insulation properties.
Packing your sleeping bag
If you were ever in Scouts or Guides you may have been taught to pack you sleeping bag away by rolling it very tight and then carefully sliding it into the carry bag before carefully compressing the last bits of air out of the bag. Release the compression straps as much as you can, and pack your sleeping bag in by stuffing in from the bottom, once it’s in carefully go round the compression straps working them down one by one, working from opposite sides can help, so tighten one strap and then the opposite strap, then moving round the circle carefully. Always shake out your bag before packing it away, there is nothing worse than finding a mouldy bit of the midnight snack from camping when you unpack your sleeping bag.
Stuffing it in also means that you won’t be compressing the same part every time, rolling can mean that you flatten the same point of the sleeping bag every time.
Carrying your sleeping bag
Your bag needs to be kept dry, especially if it’s down filled, you can buy waterproof bags for your sleeping bag so that you can tie the sleeping bag to the outside of your pack, as one of the bulkiest pieces of kit that you’ll carry its often worth carrying it on the outside of your bag.
Washing your sleeping bag
This is intended as a guide only, check the wash and care instructions on your sleeping bag before washing or cleaning.
- Air your sleeping bag as soon as you can, clean any stains on the outside with a damp cloth, if you’ve been using a liner its probable that your bag will be clean inside.
- If you need to clean it properly then getting it professionally cleaned is always recommended. The use of a large front-loading washing machine and a large tumble drier will keep the insulation lofted. Many local laundrettes will offer this service.
- If you do wash your sleeping bag at home, you should hand wash it. Fill the bath with luke-warm water and about a third of the usual amount of soap you use.
- If you’re using a machine wash, avoid very warm temperatures and select the cycle based on the type of sleeping bag.
- If you machine wash, use it as an opportunity to add waterproofing. Waterproof treatments are available at most camping stores, and online retailers.
Drying your sleeping bag
Drying is the most important step, remember that bag is wet, and will be heavy. If you have a big tumble drier, and your sleeping bag is tumble drier safe then use it, but pick a low heat setting. It might be worth throwing in a few tennis balls to break up the clumps of feathers as they dry. Also be careful that if you are using a laundrette their driers can get extremely hot. If you do get it through a cycle or two, it should result in a dry fluffy sleeping bag. If you don’t have a suitable tumble drier, then hang the bag to dry. Every few hours give the bag a bit of massage and shake to break up the clumps of feathers of fibres.
What to consider before buying a sleeping bag
Before buying your sleeping bag, there are a few things you need to consider. Like, when are you going to be camping? If you’re only going to be out in the summer, then you don’t need to buy a sleeping bag that will cope with -10°C. Or, if you are camping close to your transport, weight becomes less of an issue.
Size is a compromise. The larger the bag, the more space your body needs to heat up. Conversely, the smaller the bag, the more constricted you’ll be. If the sleeping bag is for use indoors, then you may as well get a cheap, simple bag. For camping purposes in a tent or bivouac, you’ll need to select a more technical sleeping bag.
What else will you need with a sleeping bag?
Just like with your bed at home you have sheets and duvet covers, liners make it easier to keep your bedding clean, a sleeping bag liner does the same thing. Easy to take out and wash clean, and can be used to make a sleeping bag more suitable for slightly colder conditions.
Liners come in various shapes, so buy one to match the shape of your bag e.g. mummy, long, rectangular etc. Silk liners are lightweight, easy to wash and dry and a total bit of luxury in your camping gear. Silk does tend to be the preferred option for serious campers. Polycotton and cotton are the cost effective option, just as easy to wash and dry the only disadvantage over silk is they are slightly heavier, and maybe don’t feel as luxurious. Fleece liners are also available these are said to add a full season to a sleeping bags comfort rating.
Stuff sacks are a key piece of kit with any sleeping bag. Designed to store and compress your sleeping bag, they are usually supplied with the sleeping bag. It is recommended to fold the sleeping bag before putting it in the stuff sack, but the name implies the normal way of putting the bag away, by stuffing in and packing tight using the compression straps.
If your stuff sack doesn’t have compression straps, or you need extra straps to allow you to attach the bag to something else, such as a backpack or bike rack then these are vital.
Camping can be a great way to have fun, get away for a few days and get back to nature. But with the wrong equipment it can be cold and frustrating, ending with everyone huddling in the car to stay warm. Instead choose the right sleeping bag so that you don’t get cold, and don’t overheat. Make sure you’re going to be comfortable and get a great night’s sleep, so you can enjoy the next day of your holiday refreshed and ready.