Sleeping Bags

Choosing a sleeping bag can be baffling, as there seems to be an endless number of bags on the market, each with a different shape, temperature rating, and insulation material. Those three components make up the major points of difference between bags, and once you've figured out which of those features you like, bag choices get simpler.

When looking at bag shapes, keep in mind that a sleeping bag keeps you warm by trapping a layer of air, warmed by your body heat, between you and the cold air outside. If you'll be camping in extremely low temperatures, a mummy-style bag will keep you warmer, as there's less area inside the bag for your body to heat up. If temperature extremes aren't an issue, and you tend to move around a lot in your sleep, a rectangular-shaped bag is a better, more comfortable choice. A bag's temperature rating (sometimes known as a comfort rating) is the lowest ambient temperature at which the bag will keep the average person comfortable. Those numbers are provided only as a guide, though, since a person's sleep comfort and temperature will depend on a lot of factors other than the bag itself, like whether or not the camper is using a tent or a sleeping pad, or how many layers of clothing the camper is wearing in the bag. When choosing a bag by its temperature rating, it's always a good idea to pick a rating that's a little lower than the lowest temperature you anticipate sleeping in, since it's a lot easier to unzip the bag and cool off a little than to produce "extra" body heat when the temperature dips lower than expected.

As for insulation, there are two major types: down and synthetic. Each has advantages and disadvantages that you'll need to factor into your choice. Down, though generally more expensive than synthetic fill, offers a better warmth-to-weight ratio, and its insulating properties will last longer. Down's insulating qualities are expressed in fill-power numbers, which refer to the amount of space an ounce of down will displace when it has been compressed and released. The higher the number, the better the insulation.

If down gets wet, though, it doesn't insulate at all, and won't until it's completely dry. A synthetic fill can still keep you warm if it's wet, is typically less expensive than down, and won't cause any allergic reactions. Synthetic fill is usually heavier than down and won't compact as well, so a bag with synthetic fill will take up more space in your truck when it's rolled up.