Down and loft
Down used in most technical sleeping bags ranges from 550 Fill Power to 800+ Fill Power. A 550 down fill bag, utilizes insulation that occupies 550 cubic inches per ounce of down. Therefore, a 750 Fill Power down occupies 200 more cubic inches of space per ounce! When choosing a down bag go for higher fill numbers, they result in lighter, more insulative bags. Consumers need to choose bags carefully since fill ratings are frequently subjective. All of Backcountry Gear Ltd.’s down sleeping bags are independently tested for accurate fill power. Western Mountaineering and Marmot use minimum Fill Power ratings of 750 fill down for some of the highest loft, most efficient sleeping bags available. To learn more about premium down insulation click here.

Synthetic Insulation
By far the most prevelant synthetic insulations used today are variations on a tried and tested Hoescht-Cleanese fiber, Polarguard (one of our Gear Techs had an original Polarguard bag last 14 years). In its two newer iterations, Polarguard HV and Polarguard 3D, the size of the fibers have gotten successively smaller, while improving insulative and loft properties. Polarguard HV use a 6 denier fiber, while Polarguard 3D serives its name from its 3 denier fiber, spun longer for improved loft and compressability.

Shell Materials
Technical sleeping bag shells and liners range from 20-40 denier nylon. Other fabrics include microfibers (high thread count water-proof breathable), and W.L. Gore's DryLoft, a 1.7 oz cloth with ripstop processing and unparrelled Gore performance.

Since weight is one of the most critical factors in bag construction, there is a trade off with lighter shell fabrics, which are slightly more susceptible to snagging. Another consideration, especially when purchasing down, is the thread count per square inch of fabric. In down bags this translates to the 'downproofness' of a bag, indicating how quill resistant the bag is. A higher thread count bag keeps out dirt, grime, and moisture, but keeps in more heat and prevents stray down 'spines' from perforating the fabric (ouch). If you have any other questions regarding sleeping bag construction call our Gear Techs at (800) 953-5499.