After a day in the woods, there is nothing like slipping into a warm sleeping bag. Indeed, the combination of fresh air and exercise enables many people to sleep more soundly than at home, but it can all be spoiled by an ineffective bag allowing you to feel the chill of the night. These tips will help you choose the right sleeping bag to suit your needs.
Sleeping bags are graded according to the lowest temperature at which they will keep you warm. Resist the temptation to buy a bag for the very coldest nights you might experience – choose a bag to suit the conditions you are likely to encounter most often. The most widely used sleeping bags are designed for three-season use; these models will keep you warm on frosty nights yet not be stifling come mid-summer.
For occasional winter trips, supplement the insulation value of the bag by wearing thermal underwear and other clothing. An inner sheet or a bivouac bag will also add warmth. If regular outings are to be made above the snowline, buy a specialised winter bag rated to lower temperatures.
Sleeping bag fabric and insulation
The traditional insulation for sleeping bags is down. Despite advances in synthetic insulation, it still provides the maximum warmth for a given weight of fill. Nothing synthetic quite compares to the soft, luxurious feel of a down bag. Though generally more expensive than bags with synthetic fill, they are a good long-term investment — the best models may give up to 20 years of service. Best of all, down bags compress into a remarkably small parcel for easy stowing in a backpack.
Down is vulnerable to moisture, and a damp down bag is a liability because it retains warmth less effectively. Synthetic fills, by contrast, continue to provide insulation even when wet. For travel in a predictably damp environment or when canoeing or rafting, a synthetic sleeping bag is a sensible choice. Synthetic bags are also easy to clean, non-allergenic and can be less than half the price of a similarly rated down bag.
Regardless of how good your sleeping bag is, its effectiveness is severely compromised if there is not adequate insulation between it and the cold ground. A pad made from closed-cell foam or a ‘self-inflating’ sleeping mat is essential.