With the "white stuff" that appeared this week, it's time to start talking about staying warm with the other "white stuff", i.e. natural goose and duck down.
What is down?
A common misconception is that it's simply small feathers. This is unfortunately a myth propagated by manufacturers who try to sell feather-filled jackets and pillows calling them "down", when in reality many of them contain as little as 5% actual down. Now before you run home and look at your pillow tags and get all pissy because the nice lady at Bed, Bath, and Beyond lied to you, understand that for pillows a mix of down and feathers is just fine, because a truly down pillow would actually squash flat when you rest your head on it, which is kind of defeating the purpose, right? But enough of this pillow-talk, today we're talking about apparel and sleeping bags.
So if it's not just small feathers what is down really? Down is actually the small tufts that sit underneath the feathers closest to the body of the bird and provide the insulating layer that keeps the bird warm. Down works by trapping small pockets of air between the filaments. This trapped air warms from body heat and provides an insulating layer of warmth. Another way to think of it is this, down is like the insulation in your attic, while feathers are like the shingles above, their sole purpose is to act as protection and keep the insulation from being exposed to the elements.
So Down = Insulation vs. Feathers = Shingles, got it?
If you're somewhat familiar with down, you've probably heard the term "fill power". You might have also guessed or been told that higher is better, but why?
The higher the fill power:
- the more air each filament traps
- the higher the loft of the down
- the better the insulating power (R value)
- the lighter the item that contains the down to provide the same warmth
Down is rated, or measured, by a number between 400 - 900. What this means is that one ounce of 400 down will expand to fill 400 cubic inches of space; and one ounce of 800 down will expand to fill 800 cubic inches of space. With the exact same weight of one ounce of down, but double the lofted volume in the 800 fill power, the 800 is a much better insulating down ounce for ounce. And higher insulating power = warmer.
The reason for the difference in loft is that the consistency of down is not feather like, but is actually more like snowflakes. Some pieces of down are 2-dimensional; think of the flat snowflakes we cut out of paper. They trap a little bit of air in between the spaces, but obviously not a lot, these are what we rate as 400 down. Other pieces of down are like the wonderful big fluffy snowflakes that almost look like little balls of fluff as they fall. The reason those snowflakes feel "fluffy", is that they are large clusters that trap a lot of air, this is a good example of what 900 fill down looks like. Then there is obviously a broad spectrum in between.
Now you may ask, why can't you just put more of the lower rated down in the same space to achieve the same warmth? You can, but you pay the price of doubling the weight and bulk of the garment or sleeping bag.
You know the stereotypical "Michelin Man" look many people think of when they think of down jackets? That's 400 fill down. An 800 fill jacket will give you every bit of the warmth with half that bulk and much less weight. I have a 850 fill jacket that weighs less than 15 oz. and is a very slim fit. I barely even notice that I'm wearing it, and can actually layer it under a fleece jacket if necessary. The best part is that it keeps me warm down to -20F, no joke.
So why aren't all jackets 900 fill? Because there is very little 900 fill down available. It is typically only found on mature geese, and very little per bird, so it's precious and expensive. On top of that, 750+ fill is only collected by hand when geese or ducks go through the natural molting process. How about that for a job? Just walk around the farm yard picking up little tufts of down all day.
So what fill power down is right for me? It depends on your personal preferences, the items' intended use, and of course, your budget.
For casual styles of outerwear, there's nothing wrong with having a lower fill rating, because weight is typically not a huge concern, and most people just can't justify a $300-$500 price tag for a jacket. For that reason, expect to find that most casual jackets will be about a 550 fill power, a great balance of warmth vs. cost.
For high-performance outerwear or sleeping bags, or if you just want the best, expect to see fill power ranging from 700-900, but know that with the premium product comes a premium price tag, there's no way around it. However I guarantee the benefits will warm your heart!
If you would like further information, or want to check out the differences in person, stop down and talk to us at The Gear ReSource, your local ReSource for all things Outdoors.