Whether you are going to be sleeping in a snow hole or on a sun drenched tropical beach there are sleeping bags available to suit your needs. And since you spend 33% of your life asleep, one third of your time in the outdoors will be spent in your bag- so it is definitely worth getting one that you are comfortable in. If you are a backpacker weight is a major consideration, as is packed size, so it would be wise to use these as your guiding qualities, as well as any others mentioned here.
Buying a sleeping bag can seem a bewildering experience, but armed with a few basic guidelines you can make an informed choice on the bag that best suits your needs.
First of all you should think about the conditions you will be using the bag in, there's no point in buying a bag rated to -150C for summer only camping and, conversely, if you want a bag for year round use one rated to +50C will not be sufficient. Both of these inappropriate bags would mean a poor nights sleep at best, serious danger at worst.
Comfort Rating
Bags are rated by the manufacturer to a minimum recommended temperature and also usually a "comfort rating". If there is only one temperature rating given and it does not specifically say it is the comfort rating then the figure will be the minimum temperature recommended. Basically what this means is that this is the lowest temperature the bag will keep you healthy in, but don't expect much in the way of a good night sleep near this figure! The comfort rating is a much more useful comparison figure as this is the temperature when, in normal conditions, the average person will feel comfortable enough for a good nights sleep, exactly what you need after a hard day on the trail!
But who is this "average" person? According to the manufacturers it is someone who is not too fatigued, is neither under or over weight for their size, not sleeping in the open in a bivi bag, has a normal metabolism and is using an insulated sleeping mat. This means that if you vary from this description in any way you will have to adjust the comfort ratings accordingly; for example, if you are very tired and of thin build a bag rated at +50C may feel cold at +80C and so on. Use observations of your general comfort in cold weather to guide you in the choice of bag.
Shape
Sleeping bags fall into two main groups as far as shape is concerned, each with their best uses. Which you choose depends upon the activities you are involved in and the conditions experienced.
'Mummy' shaped bags:
These are very efficient at keeping your body warm, but they have a fairly restricting shape that prevents huge amounts of movement while you sleep. The use of a hood plus baffles along the zip and around the neck area greatly increases the heat retention and gives you a bit more flexibility with regard to ventilation options. This means you shouldn't be faced with the old dilemma of opening the bag a bit and freeze or keep it zipped and sweat buckets! For my money, and by far the majority of other outdoor enthusiasts, this is the best shape to buy.
Rectangular bags:
Most bags in this category have nylon fillings and shell materials, this makes them bulky and heavy for the insulation provided, but they do offer a bit more room to move around in. Because of these limitations they are best suited to car camping and only in the warm weather of summer. Sleeping bags with quilted rectangular shapes and the Tellytubbies or other cartoon characters printed on them are not recommended for outdoor use, no matter how cute they are!
Shell
This is the part of the bag that you will be in contact with, and also the part dealing with the rigours of the outside world. There are a variety of materials in use, each with their own pro's and con's.
Dryloft: Produced by W.L. Gore, the makers of Gore-Tex. Dryloft is less waterproof than Gore-Tex but much more breathable which is a more important feature in a sleeping bag, but it is less breathable than microfibre. This shell material is best used in very damp conditions.
Microfibre: Tightly woven, very fine denier nylon or polyester fibre that sheds wind well and is not too bad at repelling moisture. Less waterproof but more breathable than Dryloft.
Ripstop Nylon: Durable nylon, or polyester, fabric with thicker and stronger threads woven into the material to improve tear strength. Sometimes treated with a water repellent to improve waterproofing.
Filling
This is the most important part of the bag, the bit that keeps you warm. There are quite a few popular synthetic fillings that are in use at the moment, plus down of course, all of which have their pros and cons.
Down: This is the best insulator for loft, warmth to weight ratio, breathability, pack size and durability. But when a down bag gets wet it loses over 90% of its warmth, gains 130% in weight and takes more than a day to dry out. Best used in very cold, dry environments.
Quallofil: Hollow polyester fibres, each with four microscopic tubes that provide more surface area and allow for greater insulating ability. Quallofil is nonallergenic and retains most of its heat when wet like all the synthetic fills, ideal for British weather but can be a bit bulky.
Hollofil & Hollofil 2: These are also polyester fibres, but are about 5cm long and so have to be sewn onto a backing material to prevent clumping and cold spots. Hollofil has a large single hole in the fibre that allows for more air per gram and so has greater insulation. But this extra insulation is gained at a price because the added backing material increases the weight of the bag.
Lite loft, Micro loft, Primaloft, Primaloft 2, Primaloft lite : These synthetic insulators come the closest to down-like feel but are not as durable as down.
The short-staple fibres are lighter and more packable than Polarguard, Hollofil and Quallofil.
Polarguard, Polarguard HV, Polarguard 3D : Long, continuous-filament fibres that are more durable and stable than short-staple fibres. They are also a bit heavier. Polarguard HV is about 20% warmer weight for weight than the original Polarguard due to hollow fibres which cut the weight by 25%. Polarguard 3D is correspondingly better than HV and is the current top of the line filling.
Specialist Jackets
These jackets represent the state of the art in waterproof activewear; utilising the best materials available plus a host of features and technical innovations to regulate temperature, manage moisture and keep you dry in the worst conditions mother nature can throw at you. If you are involved in an activity where you work hard in all weathers then these are the jackets for you.
Features to look out for.....
- If you want to join two bags together make sure you get a pair of bags with compatible zip types and a left and right zippered version.
- Two way zips allow for more ventilation options and will make your sleep time more comfortable.
- A draft collar and zip baffle will prevent cold air getting in and heat leaking out of vulnerable areas of the bag such as through the zip and out of the top.
- A Velcro tab or similar to ensure the zip will not come undone by accident during the night is a good feature to have.
- Bags that come with a four way compression sack will be able to be packed into a smaller area than those with a standard stuff sack.
How to keep your bag in good condition.
- Store the bag loosely inserted in a large cotton storage sack when not in use, not compressed!
- Always stuff your bag into its stuff sack, (kind of obvious really!), and never roll it up to stow away. Stuffing is actually easier on the shell and fill.
- Always be gentle with your bag, never yank it out of the stuff sack, this also damages the shell and fill.
- Wear clothing inside the bag or use a liner, this prevents the inside of the bag getting dirty and reduces the number of washes you have to put the bag through. This is important as with every wash the fill loses some of its loft and this degrades its insulation.
- Always use a sleeping mat or groundsheet to keep the bag off of the ground.
- Always air the bag after use.
- When putting your bag into your rucksack always wrap it up in a separate plastic bag to keep it dry. This means that you have the rucksack liner and another layer of plastic to prevent it getting wet while out in the rain. If you don't you may experience a damp, uncomfortable night.
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