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Alan Yiu Westcomb

For over 30 years, Westcomb has been keeping athletes and adventurers insulated with some of the warmest jackets in the business. They also happen to be a Canadian company and you better believe they know a thing or two about keeping warm on the coldest of days. We spoke to the brand's Creative Director and Founder, Alan Yiu, to give us a bit of a primer on what we should know when shopping for the perfect down jacket. 

What do the numbers mean?

Down is available in a range of fill powers from 500 to 900 where the higher number refers to the most loft and warmth efficiency. Qualities in the higher fill powers (800 and 900) are only available in Goose due to the bird's size compared to Duck.

What works in what temperatures?

As for 'temperature' range the main variable here is down % and amount. For our most extreme conditions we have a new Belay Parka made with 400 grams of Goose down with a minimum down cluster of 90% to be used in -40C conditions. You are able to use an inferior down at 600 grams of 600 fill for example. Basically, while there is a warmth difference when you compare gram per gram, you can compensate by using more down.  

On the strength of good down and the benefits of synthetics

Down’s achilles heel is moisture and water. As soon as the material gets saturated with water it will lose its loft and warmth until it dries out. Keep in mind that down has natural oil properties that coat the plumes so it will take some time before the material soaks. How long before the material gets saturated is a function of quantity or volume of water and time…duration in which the material is bombarded with moisture/water.

High quality down is a resilient and extremely efficient insulator. So while you may have a waterproof barrier that prevents the elements from soaking through, depending on the activity the moisture vapor/sweat from your body still exits and passes through the down. So how do you protect the material or help aid its loft? 

One method is a chemical method where the down is coated with a fluorocarbon (DWR-like) so that the material repels sweat. The negative to this is that you have to use a lower Fill Power as the higher Fill Powers aren’t as robust. Secondly, you are adding another chemical next to your body for those who care. 

One solution to a chemical option is a blend such as Primaloft’s Down Gold where approximately 30% of the total fill is 100% polyester while the balance is 750 Fill Goose Down. Bear in mind that the process to get this ‘blend’ isn’t simply filling a bag with down and polyester and shaking the 2 compounds together. This truly is an intimate blend where the ultra-fine polyester filaments are attached to the down via a proprietary treatment. The net result is an excellent insulator with enhanced wicking.

A Down Cheat Sheet

Goose vs. Duck: For premium products, you should stick to the best grade of down based on fill power which is Goose. On the lower end products (low fill power) it doesn’t matter. the only exception would be Eider down which is the only down sourced from the wild (not domestic).

Down Origin: The best down comes from mature birds (leads to larger plumes) in cold weather climates.

Down Content % vs. Fill Weight: Down weighs less than feather so rather than focus on fill weight used in a garment look at down content % where the higher the better.

Down Source: How the down is collected, cleaned and treated may also play a role in the quality that has no bearing on performance. Things like does it smell, is it ethically sourced, is there dirt / debris mixed in with the down ..all may be important depending on your value proposition.  

For more on Westcomb, visit

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