Down: Very Compact-will easily fit into your pack and are very lightweight if you are concerned with weight. Incredibly Warm - Lofts better than any other fibre and successfully traps your body heat to keep you at a comfortable temperature. Many

 

down bags feature Box Wall construction which enables you to move the down from the top of the bag to the bottom increasing or decreasing the trapped warmth when you are sleeping. This makes the bag suitable for all seasons

 

 

 

Synthetic: It's main beneficial feature is that it will keep you warm even when wet and is lower in price than the quivalent down bags

 

The ongoing development of synthetic fibres is allowing bags to become more and more compact when packed. Almost all of these bags come with a compression sack to make them smaller.

 

 

 

Verdict: Down sleeping bags are genarally more compact and warmer than synthetic bags and are a great choice when going to extremly cold climates. synthetic is the ideal choice if there is a possibility that you may get wet. They are also the more affordable option if you are on a budget. A great choice for 3-4 season use in not such extreme climates.

Please keep in mind that the temperature ratings given on these sleeping bags tend to be the extreme ratings (will keep you alive). Comfort ratings are usually around 3-5 degrees warmer. Every person sleeps at a different temperature and it is important to take this into account when choosing a bag. If you get cold when you sleep then you should choose to get a slightly warmer bag.

 

What to look for in a good sleeping bag

 

• Hood - Look for a hood that completely covers your scalp and has a draw cord that pulls in the hood so that it only leaves your face poking out. It should trap the air in around your head and neck. The photo of the sleeping bag above is a good example.
• Draft Tube - The draft tube is a strip of sleeping bag that runs down the inner of the bag next to the zip. This prevents cold air from coming into the bag from the zip and hot air from escaping.
• Neck Muff - This is important in helping to trap the heat in a 3 - 4 season sleeping bag. It is an extra flap of sleeping bag that runs inside the neck part of the bag. When the neck drawcord is down up, this pulls in around your chest trapping in all of the warm air (and is very soft and comfortable).
• Design - A mummy style bag is the most efficient at keeping you warm as there is less space inside the bag to heat up. A mummy style bag with a box foot is excellent as this gives your feet a bit of extra room so that they can stand up straight if need be. Rectangular designs are good for family camping in warmer whether as they give plenty of room to spread out and can be unzipped and opened out to form a blanket. It is also a good design for backpacking.
• Anti-snag/Auto-lock Zips - There is nothing worse than fighting with your sleeping bag zip in the middle of the night and having it snag on the fabric. Many sleeping bags (including Outer Limits) as stitching their zips in such as way as to prevent the zip from catching on the surrounding fabric walls. Good bags have auto lock zips so that the zip locks in place and doesn't undo all the way down while you are sleeping.
• Zipping 2 Bags together - A handy feature with most sleeping bags is that they come in both left or right hand zips. This means that you can zip 2 bags together to make a double. The sleeping bags are usually only compatible with the same model but some bags may be compatible within the same range. This usaully works best with rectangular shaped bags and will only work with bags that have a full length zip. 
• Lining - A soft polyester lining like Siltec or even nylon is better when sleeping in a techical bag. This is because it breathes and helps to wick away moisture. Cotton is comfortable and is often used in the form of flannelette in family camping bags. The down side is that it can hold moisture leaving you feeling damp.

Tips for Maintaining or Increasing the Warmth of Your Sleeping Bag

• Thermals - wearing thermals/polyprop when you sleep will help to maintain optimum body temperature while still allowing your body to breathe.
• Sleeping Bag Liners - Using sleeping bag Liners is a great way to keep your sleeping bag clean and will increase the temperature of your bag by about 2 degrees.
• Bedding - many people are cold in a sleeping bag even though it is rated as being very warm. This may be due to incorrect insulation under the bag. Almost 70% of body heat can be lost into the cold ground if inadequate of no base insulation (mat) is used. A closed cell foam mat insulates very well from the cold ground and is an inexpensive option. A more comfortable option is a 3 or 4 Season self inflating mat depending on what the weather is like.  Airbeds or blow up beds generally have no insulation so that trap cold air,  sucking out your warm body heat.
• Food - Eating a meal before bed, kick starts your metabolism, giving you more energy to stay warm.
• Go to Bed Warm - If you are cold when you get into your sleeping bag, chances are that you will stay cold throughout the night. You need to be warm in order to heat the trapped air inside the sleeping bag. The sleeping bag just maintains this warm air.