Our reviewers carried these jackets to the summits of alpine peaks and to the depths of cold desert canyons to evaluate each jacket on our extensive set of evaluation criteria. We wore them under shells and over thick base layers, at belay stations, and around camp. We crammed them into our packs and wore them under backpack straps. We clipped them to harnesses and jammed them in crack climbs. We took them to Antarctica to test them in the biting wind while hiking and living on the ice. We researched and verified the specs and details of these jackets, and compared these notes with our findings in the field.
We exposed these jackets to cold drips on ice climbs in Montana and inclement weather in the Pacific Northwest. We toted waaaay too many down jackets on every adventure so we could compare them in similar field conditions. Noting the temperatures and conditions, we evaluated how warm each jacket was relative to the others, ranking them on a spectrum. Then we compiled the information from each jacket's technical specifications, notably the quality of the down and the wind resistance of the materials, to complete the picture of how warm each jacket feels.
This was one of the simplest tests: We just weighed each jacket on a hanging scale, with the stuff sacks they came with.
Compressibility was another metric which was scored relative to the other jackets in the review. We first stuffed each jacket in its pocket or stuff sack, if it had this feature, then lined them up from poofiest to least poofy. That's the technical terminology. We then made some more qualitative notes for each jacket, such as how easy it was to stuff into the pocket or stuff sack, because a compressible jacket is just annoying if it has an overly-ambitiously-small pocket or stuff sack that is impossible to cram it into.
For this metric, we listed all of the features of each jacket, so more fully-featured jackets came out ahead in this category. However, we also weighed in our opinions on how appropriate or useful the features were, and if they made sense for the intended purposes of the jacket. For example, an ultralight-focused jacket would get a single point boost for having thoughtfully selected features that align with the goals of keeping it super ultra-light, but also make it more user-friendly. This is the trickiest metric to balance in lightweight down jackets.
For this metric, we took each jacket out into the wilds, where it belongs. We focused on the activities and environments for which each jacket was intended. This means that for stylish, urban-focused models we mainly adventured around town wearing the jacket, and for ultralight models for cold weather mountain use, we took them ice climbing or ski touring. We assessed how well the jackets held up to use over several months. Then we reviewed the denier rating of the materials, as well as the design features, stress points, and zippers, to paint a more complete picture of how durable we expect each jacket to be, in the longer term.
Down jackets are not meant to be waterproof, but since down loses its insulating properties if it gets wet, it is good to have a water-resistant material to shed a few drops or a light mist. We assessed the water resistance on wet days in the field and ran the material under running water to see how well it shed water.
Sometimes in this review, jackets turn up with hydrophobic down. While this technology is not currently dominating the market, we have assessed it in the lab by extracting a sample of the down from one of our test jackets to examine the look and feel of the down. The down looked no different to the naked eye. Then we sprayed a mist onto the sample and watched water bead up on the surface of the fibers instead of soaking in immediately. This technology seems to be fading from favor in the industry, likely due to cost, complication—and minimal benefits. In our experience (and opinions), the external fabric seems to be a better place to put effort and dollars into designs that keep your down dry and your body warm.