Camping Gear

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

Posted On December 6, 2016 at 4:04 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.

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.

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.

The Big Outside is proud to partner with these sponsors. Please help support my blog by liking and following my sponsors on Facebook and other social media and telling them you appreciate their support for The Big Outside.

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.

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.


Do you like The Big Outside? I’m Michael Lanza, the creator of The Big Outside, recognized as a top outdoors blog by a USA Today Readers Choice poll and others. Get email updates about new stories and free gear giveaways by entering your email address in the box at the bottom of this story, at the top of the left sidebar, or on my About page, and follow my adventures on Facebook and Twitter.

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.

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.”

Some of my favorites are:

Patagonia Nano Puff Hoody (read my review)
Outdoor Research Uberlayer Hooded 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 “10 Smarter Ways to Think About Your Layering System” and 5 Tips For Spending Less on Hiking and Backpacking Gear.


In Ask Me, I share my response to a reader question. Got a question about hiking, backpacking, gear, or any topic or trip I write about at The Big Outside? Send it to me at, message me at, or tweet it to @MichaelALanza. I will answer the ones I can in a blog post, using only your first name and city, with your permission. I now receive more questions than I can answer, so I ask that readers sending me a question be willing to make a minimum $25 donation to this website through my Support button for the time and expertise I put into a response. I will also provide a telephone consult for a minimum $45 donation. Write to me first and I will tell you whether I can answer your question (I usually can); I will respond as quickly as I can. First scroll through my Ask Me page and All Trips pagesskills stories, and gear reviews for answers to your questions before writing to me.

—Michael Lanza

This blog and website is my full-time job and I rely on the support of readers. If you like what you see here, please help me continue producing The Big Outside by making a donation using the Support button at the top of the left sidebar or below. Thank you for your support.


from The Big Outside

Visit Us On FacebookVisit Us On Google PlusVisit Us On Youtube