DWR treated down – How Effective?

I’d say, effective enough.

It’s worth noting that a number of the high-end down equipment makers have decided not to offer treated down. This includes:

• Feathered Friends:Treated down (“dry down”) is a technology that was developed to decrease drying time for hotel comforters in commercial dryers, and we very purposefully do not use it in any of our products. Besides decreasing the longevity of the high-quality down we use by stripping the down of its natural oils, we’ve also seen little real-world benefit to the use of durable water repellency (DWR) directly on the down plume. Wet down clusters do not insulate, regardless of any coating applied to keep them dry, and we’ve found that body heat or ambient air flow — rather than a dryer– isn’t sufficient to make dry down an effective tool in keeping you dry, and therefore warm. Treated down is also more prone to clumping than untreated down, which makes it tricky to keep properly lofted within a garment or sleeping bag. The bottom line: untreated down will last longer and perform better than treated down, a view shared by some of the field’s leading manufacturers
• Western Mountaineering:We have found in our own testing that the performance enhancements of hydrophobic treatments on high quality down are widely overstated. High quality untreated down already has naturally water repellent oils on it left by the geese (makes sense since geese spend a lot of time in water). These oils help repel water and keep down lofted. More importantly is that these oils last indefinitely. Hydrophobic treatments wash out like a DWR and remove the natural oils during the application process. Because of this, and the water resistant capability of our shell fabrics, we feel that hydrophobic down does not provide a considerable impact on performance and could actually inhibit performance over the lifetime of our products.
• PHD Designs: The longevity of treated down and the speed of deterioration of fill power is a concern to us. High quality, well processed natural downs are actually already very hydrophobic