Down filled products, sleeping bags, and quilts have been the favourites of hikers and mountaineers for decades because of their outstanding insulating ability and light weight. However, they have one critical weak point, down loses its insulating power dramatically when wet. This is the problem that hydrophobic water repellent down is designed to solve, which thanks to its special treatment is more resistant to water. In this post we will present what hydrophobic down is and how it differs from the traditional version, how down filling is made water resistant including the example of Grangers brand treatment and the importance of PFC free technology, what advantages it offers in extreme wet conditions, in which gear it is worth using, and finally we will also discuss the environmental and health benefits of PFC free processes.
What is hydrophobic down, and how does it differ from traditional down:
Hydrophobic down is natural down usually goose or duck down that has been treated with a special water repellent coating. The purpose of this treatment is to make the down absorb much less water and dry faster, so that it retains its insulating ability and the loft height of the filling even in wet conditions. Normal untreated down has fine fibres that stick together when exposed to moisture, the down collapses, and the air trapped inside is pushed out, so its insulating power practically disappears. Down filling without hydrophobic treatment in a soaked jacket or sleeping bag will therefore not provide insulation until it has completely dried.
In contrast, the water repellent coating of hydrophobic down prevents or slows the down from becoming wet, so it retains its loft and insulation for longer even in damp conditions.
The main advantages of hydrophobic down compared to traditional down:
- Absorbs less water, resists moisture for a longer time without becoming soaked
- Dries faster, treated down regains its loft more quickly after getting wet
- Keeps you warm even when wet, retains some insulating ability in a partially wet state by preserving loft
How is down filling made water resistant? (Impregnation and PFC free processes):
Effect of the hydrophobic coating, on specially treated materials the water forms droplets and rolls off the surface instead of being absorbed. Down filling is usually treated during production with a durable water repellent DWR coating that covers each individual down fibre with an invisible protective layer. Different manufacturers may use different chemical solutions, modern hydrophobic down coatings can be fluorocarbon based PFC based, silicone based, or even wax based treatments.
Nowadays more and more people are looking for solutions that do not contain PFC, meaning compounds that were previously widely used in water repellent coatings. These fluorocarbon based substances repel water and dirt effectively, but unfortunately they do not break down in the environment, they can accumulate in living organisms, and they may also pose health risks.
Responsible manufacturers now prefer to use fluorine free alternatives. These include acrylic or silicone based water repellent agents that do not harm the environment. One such solution is the APT Acrylic Polymer Technology developed by Grangers, which provides durable water repellent performance without the use of fluorine.
(Note, hydrophobic treatments are not permanent, after heavy use and several years the water repellent effect may weaken, but with aftercare products such as Grangers Down the DWR treatment of the down can be refreshed at home if necessary.)
The advantages of water resistant down in extreme conditions and wet weather:
In extreme conditions such as multi day high mountain expeditions or hikes exposed to winter rain or snowfall, hydrophobic down can make a huge difference in terms of comfort and safety. While traditional down quickly collapses in such situations, hydrophobic treated down can retain its fill power for longer, which determines the loft and height of the filling in our sleeping bag. It is no exaggeration to say that hydrophobic down can be life saving in extreme cold and wet situations. Consider this, if our sleeping bag gets wet in a winter high mountain camp for example from condensation inside the tent or snow blowing in, hydrophobic treated down can still provide some insulation until we manage to dry it. In wet and cold weather, clothing or a sleeping bag compressed under our body weight can draw heat directly from our skin if the down collapses, the water repellent treatment prevents this acting like a safety net. It is important to point out a limitation, hydrophobic treatment does not make down one hundred percent waterproof, meaning it is not suitable for activities like bathing in a jacket filled with hydrophobic down. If the down becomes saturated with water to an extreme degree, hydrophobic down will eventually reach its saturation point and collapse, only later than untreated down. Therefore proper outer shell material or rain protection is still essential for the gear. In a heavy downpour a waterproof outer layer such as a rain jacket or the jacket’s own waterproof membrane is still needed, because if the whole jacket becomes soaked the wet fabric and lining will also reduce comfort, even if the down filling is hydrophobic. In summary, hydrophobic down is a useful extra protection that extends the usability of down in harsh wet weather, but it does not replace good waterproof outer protection.
When and in which gear is it recommended to use hydrophobic down filling?
Using water repellent down filling is recommended in any case where there is a risk that the down will be exposed to moisture. Typical applications are:
- Mountaineering and hiking jackets, especially in variable and rainy climates such as oceanic mountain regions, Scotland, New Zealand, or the winter rain and snow periods of the Tatra mountains. In such conditions a down jacket on its own would be risky, but with hydrophobic treatment it is much more reliable because it resists temporary rain, snowfall, or moisture coming from the body. Experience has shown that treated down resists rain for longer, dries faster, and even when damp retains its insulating ability, while its warmth to weight ratio remains as excellent as that of untreated down. Such jackets can therefore be ideal for high mountain climbs and winter hikes where snowfall, fog, or precipitation of changing intensity make reliable insulation important.
- Sleeping bags and quilts, on long distance treks and expeditions a sleeping bag is often exposed to condensation for example moisture forming on the inside of a tent wall, or to internal moisture from the vapour released by the sleeping body. Sleeping bags or quilts filled with hydrophobic down are less sensitive to these factors and retain comfort for longer even in wet and humid environments. An advantage of these products is that if they do become damp, they can be dried and put back into use much faster, which can be vital on multi day demanding trips.
- Other down filled gear, this includes down vests, down trousers, down gloves, and down booties used in extreme cold environments. In all such gear there is a chance that sweat, melting snow, or humid air will reach them. Hydrophobic treatment is useful here as well, for example in a high mountain down glove the sweat from the palm can over time dampen the filling, but with hydrophobic down this moisture is less likely to damage the insulation.
In general, if down gear is expected to be used in dry, freezing conditions for example dry cold in the Arctic or an indoor use down comforter, hydrophobic treatment is not essential although it does no harm. However, if there is uncertainty about how well the down can be protected from moisture, it is worth choosing the hydrophobic version.
PFC free technology, environmental and health benefits:
As mentioned earlier, an important trend in connection with hydrophobic coatings is PFC free production. The reason for this is that PFC compounds cause serious environmental and health problems. According to Greenpeace research, PFCs remain in the environment for many years, they spread worldwide in water and air, and they accumulate in living organisms, they have been detected for example in the liver of polar bears and in human blood. Some common PFCs such as PFOS and PFOA can cause hormonal disorders and developmental abnormalities, reduce reproductive capacity, and are carcinogenic. During traditional DWR treatments these chemicals can wash off from clothing into soil and water, further increasing pollution.greenpeace.org.
For these reasons, the use of PFC free hydrophobic down technology offers significant environmental and health benefits. Firstly, eliminating PFCs reduces the burden on ecosystems and people from these persistent pollutants. Secondly, PFC free impregnation agents are generally non toxic and safer during both production and use. For example, in the case of Grangers Down Repel, not only is the formula PFC free and environmentally friendly, but even the bottle packaging is made entirely from recycled plastic using ocean waste, further reducing the environmental footprint.(8a.hu.)
Overall, hydrophobic down technology today is not only about performance but also about sustainability. Modern water repellent down fillings make it possible to enjoy the outstanding insulation of down even in harsh wet weather, while eliminating environmentally harmful chemicals from production and from our products. This is especially important for conscious hikers and mountaineers, as the experience of being in nature can only be sustainable in the long term if we also take care of nature.
If you are looking for reliable water repellent PFC free hydrophobic down filling, you will find it here with us.
In our range you can find premium down with 800 cuin fill power treated with Grangers technology.
👉 Check it out in our webshop: KHIBU
