Whether you are camping in the back country living only on your camping equipment in the dead of winter or want a little extra protection and peace of mind in a hotel room, there is a sleeping bag liner that is right for you.
Traditionally, these liners are meant to add an additional layer of warmth in a sleeping bag. Adding a layer between the outside elements and your body can significantly increase temperatures and help to maintain them as well. The same concept that applies to double paned house windows applies here. Even with using a thin silk sleeping bag liner, you can still get additional warmth.
When purchasing sleeping bag liners, there are a multitude of options. Depending on your needs, there are different ones that will work. If you are looking simply for a barrier between you and hotel room sheets, a simple silk or cotton liner will suffice. But if you are doing cold weather camping, a fleece sleeping bag liner may be more appropriate. Most sleeping bag manufactures will also produce liners.
If possible, sticking with the same brand will give you the best fit possible. Especially if you have a mummy bag, you will want to purchase a mummy sleeping bag liner. Otherwise, you may find the larger universal liners to be too much for the size of your bag. Companies such as Kelty, North Face, and Marmot all make liners for their bags. Kelty makes a lightweight fleece liner that can also double as a blanket.
Liners can also easily be made. Fleece or lightweight material as well as some wide Velcro is all you need to make a simple bag. A pattern is not necessary and almost anybody can make their own liner. Whether you purchase or make your liner, it will sure to be a well used item.