PARAMETERS OF DOWN, OR HOW TO INTERPRET DOWN FILLING DESIGNATIONS

WHAT WILL YOU LEARN FROM THIS ARTICLE?

• What is the difference between down and feathers?
• What is the loft of down and why is it important?
• What does the cui parameter indicate?

IN BRIEF:

The highest quality jackets and sleeping bags use natural down: goose or duck down. Goose down is harder to obtain and has better insulation properties, making it more expensive. The basic parameter that determines the quality of down is loft, which indicates the volume occupied by one ounce of material. The unit of loft is cui (cuin), which stands for cubic inch.

DOWN VS. FEATHERS

Both down and feathers come from geese and ducks. Although we often use these terms interchangeably in everyday language, these materials have slightly different properties. Down is the incredibly delicate undercoating of bird feathers, located closest to the skin. It has a round shape more like a ball than traditional feathers due to its hooked, three-dimensionally arranged fibers. Down is very delicate and has unmatched thermal insulation properties, making it the most noble filling for jackets and sleeping bags. On the other hand, feathers are small plumes found around the wings and chest of birds. They are larger, heavier, and stiffer than down, and they are flat, resulting in poorer insulation properties. Feathers are also easier to obtain, which translates to a lower price.

DOWN-TO-FEATHER RATIO

When choosing a sleeping bag or jacket, it is worth paying attention to the ratio of down to feathers. The second type of filling has inferior insulation properties and is heavier, but obtaining 100% pure down is practically impossible. Therefore, most products contain a certain amount of feathers, which manufacturers indicate on the label. Typically, you come across notations like 90/10 or 80/20, which mean that the filling contains 90% down and 10% feathers or 80% down and 20% feathers, respectively. For a jacket or sleeping bag to be considered down-filled, down must constitute at least half of the filling, although the 50/50 designation is found on products of questionable quality.

NATURAL DOWN LOFT (CUI)

Loft, which refers to the fluffiness of a sleeping bag or jacket, is one of the fundamental parameters used to determine the quality of natural down as a filling. The rate of expansion translates into the amount of trapped air, hence the insulation and compressibility properties. The unit of down loft is cui or cuin, which stands for cubic inch, and the value stated on the label tells us the volume occupied by one ounce of down, which is just over 28 grams.

As you might guess, the higher the parameter, the better. But how does this translate in practice? A good result is down loft at around 600 cui, and anything above 750 cui indicates a material with outstanding properties. On some jacket and sleeping bag labels, you may come across a "+" symbol, which means that the actual filling properties may be even better. Interestingly, similar insulation parameters can be achieved using down with different lofts. However, in the case of lower loft down, more filling is required, resulting in higher weight, larger size, and poorer compressibility properties.

GOOSE DOWN OR DUCK DOWN?

We have something to be proud of when it comes to down! Polish goose and duck farms supply material whose properties are highly valued worldwide. Generally, duck down has slightly inferior parameters and rarely reaches a loft level of 650-700 cui. Only high-quality goose down, such as that derived from Polish Koluda geese, achieves values of 800-900 cui or even higher. In some jackets and sleeping bags, you may find a mixture of both types of filling, which is used to lower the price of the final product. Although duck down will never match goose down, for people who do not plan extreme expeditions, the effect should be satisfactory.

You will find the highest quality jackets and sleeping bags filled with Polish down at pajaksport.pl. We have gained the trust of professional climbers and mountaineers!

Text author: Agata Kliś-Koszykowska