Choosing the type of insulation you want for your sleeping bag is much more complex today than just picking between synthetic or goose down insulation. Today, you need to consider the different types of insulation, the construction process, and the different characteristics of each option.
Sleeping bags are typically filled with goose down or a synthetic material. Modern synthetics have been so refined and developed that they have replaced down fill in camping sleeping bags to a great extent. Although synthetics cost much less than down, a synthetic sleeping bag won’t last as long, nor will it maintain its insulating ability as well as a down-insulated sleeping bag will. The very best synthetic fills come very close to the thermal efficiency of down, but are still unable to completely match it.
Synthetic fills have many advantages that make them a better choice for most car camping trips. The fact that they are usually inexpensive is a definite plus, and a synthetic-insulated sleeping bag doesn’t require as much maintenance as a down-insulated sleeping bag. Also, synthetic fill is non-allergenic and works great for those campers who are allergic to down and feathers.
A synthetic insulation sleeping bag is an excellent choice for canoe trips and for camping in wet conditions. Synthetic bags will retain much of their insulative properties, even when wet. If you get your camping gear wet occasionally, a synthetic bag may be your best option. Unlike down, synthetic fill can maintain its “loft,” or thickness when wet, thus holding in more air and warmth. A synthetic sleeping bag is able to retain about 65% of your body heat, even when wet, which is far more efficient than wet down. And, synthetic sleeping bags dry out very quickly, making them more resistant to mildew and rot. If you do a lot of camping around water, you may prefer synthetic sleeping bag fill.
Insulation materials and quality are constantly improving, with current synthetics being developed that are closer in weight, warmth and compression to goose down than ever before. The types and forms of synthetic fibers vary greatly. Some fibers are continuous and long, others are short. Most synthetic insulation fibers used in sleeping bags have a hollow core, to help them better trap air. They are sometimes treated with silicon to improve their loft capacity.
By changing and varying the fiber’s characteristics, the fiber manufacturers can produce different desired comfort effects and improve the thermal efficiency of the fill or “batting.” Variations include changes in fiber diameter and length or the shape of the fiber cross section, the crimp, and the size and shape of the hollows inside of the fiber. Batting producers will even vary the thickness, weight and density of the fiberfill.
Synthetic fill sleeping bags usually have the synthetic fibers bonded into sheets. These sheets of insulation are stitched to the shell and lining, and they overlap like shingles on a roof. This type of construction protects against cold spots. With the shingle method any one point of the sleeping bag has several layers to prevent unnecessary heat loss.
For backpackers, synthetic insulations are a great choice for wet climates. Synthetic sleeping bags can be bulkier than down bags, however synthetics like ThermicMicro polyester, Thermal R Max, Climashield® Prism and Climashield® Apex are very close in weight and compactability.
Whatever bag you choose, be sure to talk with an expert here, or at the Campmor retail store, and tell them about your camping style.