Camping Gear

Ask Me: How Can You Tell How Warm a Down Jacket Is?

Posted On April 13, 2017 at 4:57 am by / Comments Off on Ask Me: How Can You Tell How Warm a Down Jacket Is?


With sleeping bags, we have temperature ratings. But with down/insulated/puffy jackets, what is best way to determine if a jacket will be warm or warmer or hot? Is it the amount of fill? Some but not all jackets indicate the amount of fill.



P.S. heading for Overland Track.


Patagonia Nano Puff Hoody

The Patagonia Nano Puff Hoody.

Hi Bruce,

You’re right, puffy jackets don’t have ratings like sleeping bags (which, by the way, were not uniform for many years, though there is now a uniform bag-rating system). Down fill weight is one way to tell, though it’s not a precise measure of a jacket’s warmth—it’s only a measure of the down’s weight, which is an important factor in warmth, but not the only one. And of course, PrimaLoft and other synthetic insulations have different weights and warmth-per-weight ratios.

Down fill rating does not indicate warmth. The fill rating refers to the volume, in cubic inches, that one ounce of that down fills; in other words, an ounce of 800-fill down will occupy 800 cubic inches of volume. Higher fill ratings translate to more warmth per ounce of down, so if two jackets contain identical amounts of down feathers by weight, the jacket with the higher fill rating will be warmer. But there are ultralight 800-fill jackets that obviously aren’t as warm as 700-fill jackets that have more ounces of down in them. You also pay more for higher fill ratings.


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Consider the conditions in which you’ll use your puffy jacket. Standard down feathers lose their ability to trap heat once wet, making down insulation less practical in wet environments. Today, there are water-resistant (hydrophobic) treatments for down feathers that greatly improve the ability of those feathers to repel water, dry faster, and continue to trap heat when damp. A soaked synthetic jacket is still probably going to keep you warmer than a soaked puffy stuffed with hydrophobic down feathers. In the real world, most of us rarely put ourselves in circumstances where our puffy jacket gets soaked; but consider that attribute of down and synthetic puffy jackets if you think there’s a possibility of facing that circumstance.


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Similarly, while synthetic insulation traditionally was not as lightweight, compactible, and durable as down, some modern synthetic insulation materials, like PrimaLoft, have a warmth-to-weight ratio that competes with down, and are more packable and lightweight. They’re also constructed in a way that’s likely to make them more durable than older synthetics, although down likely retains the edge there: I owned one down sleeping bag for about 25 years, using it on innumerable trips, and it did not noticeably lose any loft before I eventually sold it through a consignment shop.


Stay warm on the coldest days with my12 Pro Tips For Staying Warm Outdoors in Winter.”


The way in which a jacket is sewn matters. In short, so-called “sewn through” construction stitches the outer, shell fabric to the inner, liner fabric, creating pockets of down, but also creating cold spots at seams where there’s effectively no insulation. This method reduces a jacket’s weight and often its cost, and is practical in ultralight jackets. The more-expensive method of creating so-called box baffles eliminates those cold spots and makes a jacket look puffier, but adds weight and usually cost.


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Mountain Hardwear StretchDown Jacket.

Mountain Hardwear StretchDown Jacket.

Having a hood certainly keeps you warmer and is worth the nominal additional weight and cost. I consider a hood mandatory in cold temperatures (near and below freezing), but less important on milder trips, when I’ll pack a hoodless, ultralight puffy jacket to reduce pack weight and because I’m bringing a hat, anyway.

With down jackets, I generally simplify it to the following standard, which applies to my body (I don’t get cold easily) and will apply differently to other people, depending on how easily they get cold:

•    For summer trips, when I’m trying to backpack ultralight and I expect temps no lower than the upper 30s or higher, I bring a down/puffy jacket weighing 8 to 10 oz. (total weight), and I supplement with my other layers or get in my bag when necessary.
•    For trips when the temp could dip below freezing, I want a jacket that’s 12 to 16 oz.
•    For colder trips/winter, my jacket weighs 18 to 22 oz.

I find occasional exceptions to that general rule, when a jacket is remarkably warm for its weight, usually because of the use of lighter materials, such as shell fabric, and construction methods that reduce weight.

Marmot Boy's Guides Down Hoody

Marmot Boy’s Guides Down Hoody.

Find the best insulated jackets by reading my reviews of down jackets and all of my reviews of insulated jackets (including down and synthetic insulation), and see my “Review: 6 Super Versatile Layering Pieces” and “Review: The Best Gloves For Winter.”

I’ve listed here some of my favorite down and synthetic puffy jackets; the names are linked to online retailers where you can purchase them (and support my work on this blog by making a purchase through any of those links):

Patagonia Nano Puff Hoody (read my review)
Outdoor Research Uberlayer Hooded Jacket (read my review)
Mountain Hardwear StretchDown Jacket (read my review)
Big Agnes men’s and women’s Hole in the Wall Jacket (read my review)
Mountain Hardwear Ghost Whisperer Down Jacket (read my review)
L.L. Bean PrimaLoft Packaway Fuse Jacket (read my review)
Marmot Boy’s and Girl’s Guides Down Hoody (read my review)

You might be interested in my stories “What Should I Wear? How to Dress For Outdoor Adventures” and 5 Tips For Spending Less on Hiking and Backpacking Gear.


NOTE: I can help you plan the best backpacking, hiking, or family adventure of your life and answer questions you have about gear and other topics. Got a question about any trip or topic I write about at The Big Outside? Send it to me at For just $30, I’ll answer your questions via email to help ensure your trip is a success. I will also provide a telephone consult for $50. Write to me and I will first tell you whether I can answer your question (I usually can). First scroll through my Ask Me page and All Trips pageskills stories, and gear reviews for answers to your questions before writing to me.

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