The Thorium SV is a subtly innovative jacket, hiding most of the ingenuity of its design under the surface of its outer material. Featuring a composite of down and synthetic insulation, the Thorium SV stands up to weather and wear. It's box baffle construction adds bulk but also significant warmth. Though not as flashy as some other jackets in this review, the solid simplicity of its design made fans out of our testers. We tested the Thorium SV in some extreme weather conditions in New Zealand and Antarctica and came to the conclusion that no matter how often you're out, the Thorium SV will keep you protected from the weather. The jacket most similar to this one is the Marmot Guide Down Hoody, although that one ended up ranking slightly higher.
The thick and durable Arc'teryx Thorium SV is warm enough for the bad weather days in Antarctica.
This jacket was designed for comfort in a storm and it achieves its goal. Arato 40 denier ripstop fabric and a snug fit more than make up for a lower 750 fill-power rating in the Thorium SV Hoody. Critical areas (areas more likely to get wet, or potentially torn, such as the hood, underarms, and shoulders) are insulated with Coreloft synthetic insulation, only a minor concession to warmth and a great contribution to the durability of the Thorium SV. Though it will not replace your heavyweight or expedition parka, it is an excellent stand-alone for cold environments. This jacket was the second warmest in the review, behind only the Marmot Guide Down Hoody, and for most people is plenty warm enough to use as an everyday jacket in the winter. As such, we awarded it nine out of 10 points for warmth.
Close up of the box wall construction of the Thorium SV. Box baffles make it easier for the down feathers to fill the entire baffle, seam to seam, and ensure fewer cold spots, making for a warmer overall, but heavier, construction.
Front view of the Thorium SV with the hood deployed. You can see that it is indeed a very thick and burly storm shelter to be worn as an outer layer, and not likely to be layered on top of. We loved the long length and the big fat box baffles for warmth.
Heavier but warmer than most of the other jackets we tested, the Thorium SV weighs 1 lb. 7.1 ounces for a men's size large. To put that in perspective, it is half the weight of a Denali-worthy expedition parka, but offers way more than half the warmth. A fully featured jacket with a drawcord in the hem, adjustable hood cord, four pockets, and elastic cuffs, the Thorium SV is still very light for how warm it is. To take it to places that are higher or just colder, use it with another light down or synthetic insulation layer underneath. While still fairly light, in this review of lightweight down jackets it was the second heaviest overall, more than double the weight of the Mountain Hardwear Ghost Whisperer Hooded, and so understandably received a score of only three.
The outer face fabric of the Thorium SV is a 40 denier fabric that is moisture resistant and DWR treated. Additionally, this jacket features Coreloft synthetic insulation in strategic areas that are prone to getting wet from the elements or through perspiration/respiration. This is an innovative solution to the down problem that chooses a different route than the hydrophobic/DWR solution used in the Marmot Guides Down Hoody, this jacket's most similar competitor.
However, the untreated (non-hydrophobic) down still loses virtually all of its insulating abilities when wet. This jacket recovers well from washing, even regaining loft lost from repeated packing, but it takes a long time to dry. In anything other than a dryer, this jacket could take days to fully dry out, a hard thing to accomplish in the field, especially in bad weather. Try to keep this jacket dry in the field and it will serve you better. That said, it warranted seven out of 10 points, roughly middle of the field for water resistance.
Though down traditionally fares better than synthetic insulation under compression, the portions of Coreloft insulation retain loft very well. The jacket comes with a stuff sack that enables the owner — with a little effort — to get the Thorium SV down to a fairly small size. It was the only jacket in the review to come with a separate sack, and while we liked that it offered more than the Western Mountaineering Flash XR in this regard, we wonder why it wasn't designed to simply stuff in a pocket. The sack is just one more thing that you need to keep track of and not lose in your gear pile, or on a trip. While it stuffed to the same size as the Patagonia Down Sweater Hoody, we deducted a point due to the stuff sack. Five out of 10 points.
The 10 jackets in this year's review stuffed into their own stuff sacks or pockets, with a nalgene bottle for comparison. Left, bottom to top, smallest to largest: Canada Goose Hybridge Lite Hoody, Mountain Hardwear Ghost Whisperer, REI Co-op Down Hoody, Outdoor Research Transcendent Jacket. Right, bottom to top: The North Face Trevail Hoodie, some blue jacket we cut from the review (stuff sack), Patagonia Down Sweater Hoody, Marmot Guides Down Jacket, Arc'teryx Thorium SV (stuff sack), Western Mountaineering Flash XR (no sack, stuffed into its own hood).
Cool but low-key color options give the Thorium SV an advantage over your standard down jacket. Though designed for climbing, the Thorium SV would be at home at the ski resort or on your morning commute, assuming you live someplace cold. The downside is this jacket does have that Michelin Man look, increasing your visual bulk, unlike the svelte fashion of the Patagonia Down Sweater Hoody. Six out of 10.
The Thorium SV has an interesting blend of insulation inside. The main part of the torso is filled with 750 fill power down, while areas on the body, such as the hood, shoulders, and arms, that are more likely to get wet in a storm feature Coreloft synthetic insulation that doesn't lose its insulating properties when wet.
Like everything else in this jacket, its features linger somewhere just beneath the remarkable. Instead, the jacket has precisely what it needs to function well without any obvious deficiencies, sort of like The North Face Trevail Hoodie. One of our testers characterized the performance of the Thorium SV very concisely by saying, "There is nothing wrong with it." This includes the features chosen for the jacket. With no drawcord in the hood and no Velcro on the cuffs, the design of the Thorium SV is very pared down. Relying on elastic to keep the hood and cuffs snug over your helmet and gloves, the Thorium SV retains functionality in the absence of adjustability. While it does have a waist drawcord, the extra loops of elastic cord hang down below the waist, unlike the many jackets that have them hidden in the hand pockets. It also has an internal stash pocket, but only one, and it's quite small. Overall, we have come to expect a bit more thoughtfulness out of the usually very well designed Arc'teryx products, and this one is simply average. Seven out of 10.
Great protection of the face is offered with this jacket, although we wish that for ultimate adjustability there were cinch cords on the sides of the face instead of the simple elastic.
The internal stash pocket is one of our favorite features for a down jacket or belay jacket. We only wish that this jacket had two of them instead of only one.
This is one jacket that actually lives up to its recommended uses. While it's a little warm for actually climbing in, it's definitely rugged enough to survive contact with the rock. This jacket is a good belay jacket for lower altitude climbing. A great warmth-to-weight ratio and decent style make this jacket great for travel and commuting as well.
Though pricey at $425 dollars, the Thorium SV will endure more than one season of heavy use. The crux of owning a piece like this is that you probably won't want to climb Denali in it, and there are definitely cheaper layering options. If you can get past the sticker shock of its price tag, the Thorium SV is very durable and more than passably stylish, a worthy edition to your pack whether you're headed to the office or the great outdoors. That said, there are higher performing jackets in this test at much better prices, like the Marmot Guides Down Hoody.
This is a well designed and constructed jacket that will outlast its initial expense. The frequency with which we reached for the Thorium SV is testament to how well it performed for us. Whether for cold weather travel, commuting, or climbing, the Thorium SV will work for you. That said it was not one of the highest rated jackets in this review, and it lacked some of the overly thought out features we have come to expect from Arc'teryx products. This is one of the few times that we would recommend taking a peek at other, more reasonably priced jackets.
The Thorium SV is a well-featured, if heavy, jacket. It works great for photo expeditions in Antarctica.