Mike's Backpacking Reference

Bedroom

Sleeping Bag Insulation

Down

Goose down is the lightest and most compressible of the common sleeping bag insulation materials. It is also the most expensive and least durable. Down must be kept dry to maintain its warmth (loft). Fill power is the most frequently used measure of down quality. It involves measurements taken of a one ounce sample of down in a Plexiglas cylinder with a weighted piston compressing the down. All other things being equal a p sleeping bag made with high fill power is lighter and more compressible than an equally warm one made with lower quality down. Fill power is expressed as cubic inches per ounce -- a lofting power of 400-450 is considered medium quality, 500-550 is considered good, and 600-700 is considered excellent.

Polarguard

Has a number of variants "3D", "HV". It is a synthetic continuous filament polyester has the characteristic durability and warmth for which the Polarguard name has become known. Unlike cut staple insulation, Polarguard will not mat, clump or pull apart. This eliminates the chances of thin or cold spots developing in the insulation. Newer variants have a finer filament denier (diameter), which makes it softer and more compressible, with added warmth. Like all syntetics it retains warmth better than down when wet.

Hollowfil

A polyester fiber with a short staple length. This is an older technology and not commonly used in higher end products. Like all syntetics it retains warmth better than down when wet.

Qualofil

A polyester fiber with a short staple length. Quallofil compresses better than Polarguard, but over time will loose loft. Like all syntetics it retains warmth better than down when wet.

PrimaLoft

A polyester fiber with a short staple length. PrimaLoft Gold has performace charastics simplar to down both in warmth and compressibility. Silver and Black products have less insulating qualities, but may come mixed with down. Like all syntetics it retains warmth better than down when wet.

Thermashield

Thermashield is a .7 denier slickened polyester staple fiber with seven tunnel-like holes running through it. The fiber is slickened with a silicone coating on the outside of the fiber to help repel moisture away. In a sleeping bag, body moisture travels through the bag and away from the sleeper's body. Thermashield is comparable to the Quallofil ® fiber. In material and construction, they are identical; however, Thermashield is significantly more economical. (From Eureka)