Down Guide

What down is good for?

Did you know that down is the best natural insulating material on earth? Despite the expansion of synthetic materials, it still retains its leadership, thanks primarily to its unbeatable heat-to-weight ratio. This means that there is no better material than down in terms of heat retention per unit weight. All this comes with its compact pack size, which is a particularly advantageous parameter when traveling. But what do the different parameters given to the down jackets, such as FP, down/feather ratio mean.


FP as Fill Power

Fill Power (or CUIN) is a measure of the ability of down to absorb air, an important parameter in a down jacket. Higher FP down can trap more air bubbles between the fine down fibers and thus fill more space and have better thermal insulation than lower FP down. FP is the result of a laboratory test that measures how many ounces (27.3 grams) of an ounce (27.3 grams) of down can fill a measuring cylinder. That is, e.g. 1 ounce of 800 FP down will fill 800 cubic inches in the drum. In the case of down jackets, the FP value usually starts at the entry level 550 and lasts until the high-end models with the FP 900. However, it is important to know that the FP value alone does not necessarily indicate how warm the jacket will be, as the heat retention capability also depends on other parameters, e.g. weight of down filling (see below).

The weight of down filling

Although most manufacturers do not provide the weight of the down, in order to get a full picture of the heat retention capacity of the chosen down jacket - whether it will be warm enough - it is not enough to know the FP filling power. Why is this important? Theoretically, 50g of 900 FP down will be as warm as 100g of 450 FP down. It is very important that you know both parameters when choosing a down jacket and make the final decision based on this and your future use. For example, a combination of high FP / low fill weight is ideal for extreme hikers where low weight and high compressibility are very important. For everyday use, hiking or skiing, it is better to choose a model with a higher fill weight and even a lower FP value, taking into account our own warm demand.  Even so, the total weight of the jacket will be very low compared to non down jackets.


Down / Feather ratio

The down / feather ratio shows the percentage of down and the percentage of feather in the filling. Numbers represent percentages, e.g. 70/30, 80/20, or 90/10, where the first number indicates the percentage of the filling that has better heat retention down, while the second number indicates the percentage of the less heat retaining feather. But why is down better than a feather? The feather is the outer part of the bird's feather, which is stronger and harder than the down underneath, which is much softer and absorbs more air between its fibers, thus providing better heat insulation. Top quality jackets usually have a 90/10 down / feather fill ratio. And of course, here too, a 600 FP 90/10 jacket will be warmer than a 600 FP 70/30 jacket. Each IFLOW's down jacket has a 90/10 down / feather fill ratio.

Water repellent

 The most controversial, and often disadvantageous, feature of down filling is that it loses its thermal insulating capacity when exposed to moisture. In fact, when down is exposed to moisture, the ability to absorb air is significantly reduced, making it less able to retain warm. For this reason, manufacturers make the outer layer of jackets either from a water-repellent / water-resistant material or by adding additional water-repellent treatment to moisture. The most well-known and one of the best technology is the Durable Water Repellent (DWR) treatment.


How to wash

If we are over choosing the most suitable down jacket for us, then there is nothing left but to enjoy all its benefits and make sure it lasts as long as possible. First and foremost  hang it in a well-ventilated and dry place if possible and never keep it in the compression bag for long periods of time. Storing in a compression bag is very advantageous when traveling, when small pack sizes matter, but in the long run, the down is harmed by its permanently compressed state.

The second important issue is cleaning the down jacket. However, the down is washable but requires special care. Always use a special detergent for delicate washing. It is advisable to rinse the washing machine with an empty wash before washing to remove any detergent residue. To protect the outer layer of the jacket, it is advisable to put it in a wash bag to protect it from damage. Set the washing machine up to 30 °C for gentle or wool washing and spin at low speed, but avoid spinning if possible. It is important to read the washing instructions on the jacket label before selecting both the washing temperature and spin, and make the correct adjustment based on it! It is customary to put 2-3 tennis balls in the washing machine along with the jacket, which increases the cleaning efficiency and prevents the down from clumping. After washing, do not unscrew and always lay it dry and not hanging. The clumps of down slowly return to their original shape as they dry and fill their place. The complete drying process can take up to 4-5 days. Drying can also be done with a tumble dryer program.

Synthetic down

Synthetic down is an increasingly popular artificial alternative to real down. Usually it consists of polyester fibers, which try to imitate the ability of the real down to absorb air. Although it works on the same principle - the body heat is bound by synthetic fibers - synthetic down is generally less warm, heavier and less compressible than real down. It also loses its size over time and therefore has a shorter lifetime than down. However the main advantage of synthetic down is that it is able to preserve its abilities when exposed to wet weather. Synthetic down do not lose thermal insulation when exposed to moisture and can dry quickly.