Natural Fibers Versus Synthetic Materials

For centuries, mankind has known that natural fibers such as down and wool provide superior insulating qualities. But is there really that much difference between these and manufactured materials? A recent study published in the February 5 issue of Science magazine suggests not. The authors of the article found that the heat transfer through samples of down, wool and different kinds of synthetic fibers like polyester was much the same under controlled laboratory conditions.

While down has a very slight edge in insulating properties over the other materials, the difference is so small that it is not likely to be detectable by the consumer. Down does, however, have a decided advantage in the ratio of weight to insulation, being only half as heavy as an equivalent insulating unit of polyolefin, for example. The authors suggest that factors other than thermal insulation such as weight, drapability, durability and cost should be the major factors in selecting outerwear. In the long run, the effects of moisture and bellows action produced by the wearer's activity may outweigh thermal insulative values.

Finally, the single most important quality in the insulating property of a material is its capacity to "loft," or contain air. It is the trapped air, after all, which provides the insulation in the first place. In other words, if it's puffy with many tiny contained air spaces, it's good.