Down vs. Synthetic Insulation
This is question number one when looking for an insulated jacket - Do I want down or synthetic insulation? The answer largely depends on your intended use. Down is a superior insulator in many respects - it is warmer for its weight, and is much more compressible than synthetics. Moisture and wet weather however, are down's kryptonite. When wet, down is unable to maintain its loft. It loses its ability to keep you warm. This is where synthetic insulation is able to shine - though not as warm for its weight, and less compressible overall compared to down, synthetic insulations are much better at maintaining their loft when wet, and are therefore able to somewhat insulate you even when wet. So which is better? This depends. If you are recreating in weather that is primarily dry, say the desert, or in very cold conditions where moisture is low, down is the best performer. In wetter climates however, like the Pacific Northwest, or in areas with variable or unpredictable weather, synthetic insulation is the safer choice. Many backcountry travelers prefer synthetic insulation for this reason - performance when wet. If you and you jacket get soaking wet and night falls, a cold night with a wet down jacket is a recipe for hypothermia, whereas a jacket insulated with say, Primaloft, is going to be uncomfortable, but perhaps ok. Keep in mind that precipitation is not the only moisture that can compromise your down. The moisture created by your own body, via perspiration etc is also a concern over a longer trip if you don't have dry weather to dry you jacket.
Long-term durability is also a concern. Generally speaking, down is more durable over the long haul, and can be revived with a correctly executed wash of the jacket. Synthetic insulation is generally cheaper overall, but loses its loft and warming capability in shorter time. Expect a synthetic insulated jacket to last maybe 5-10 years, depending on use, perhaps even less if you use it hard and often. A down insulated jacket can be effective much longer, if taken care of.
Synthetic insulated jackets are however more "user friendly." When they are dirty, you throw them in the wash. Down on the other hand is much more difficult to clean. You need a front loading washer, a safe detergent, and tennis balls for the dryer. This is a pretty big advantage for many people. Maintenance is quick, and it's easy.
Put simply we feel there are two primary reasons you would choose synthetic over down - 1. Cost. 2. Performance when wet.
Types of Synthetic Fills
Synthetic insulation, like down, is available in varying quality - some are better than others, and some are designed for specific applications. Here we will try to illuminate the differences of those most widely available. Let's start with two basic types, and then later we will discuss specific brands.
"Short staple" insulations are made up of short fibers, less than two inches long. Body heat is trapped in the space between the fibers providing you warmth. Short staple style construction allows the insulation to be compressible, and soft. The downside to this style of construction is that overtime the insulation may migrate a bit and cause uneven heating. Because of this, short staple insulations is usually quilted into the jacket, and/or used with a stabilizing fabric inside the jacket, adding a bit of weight.
These insulations are constructed from long continuous lengths of fibers. The advantage to continuous filaments insulation is durability over the long term, and its stability within a garment. the disadvantage is a decrease in compressibility compared to short staple insulation.
Below is a brief description of the brands of insulation you'll encounter-
Primaloft is perhaps the most common insulation fill used, and it comes in several types - Primaloft ONE, Primaloft Sport, and Primaloft ECO are the three most often seen. These three are "short staple" insulations. All Primaloft insulations are treated to make them highly water resistant.
-Primaloft ONE is widely considered to be the industry best when it comes to synthetic insulation, and the standard in terms of warmth to weight ratio. It is made with extremely thin individual "microfibers" and provides insulation by capturing body heat in the countless tiny air pockets that exist between these fibers. The thinness of the fibers allows not only for more trapped air in a given amount of insulation, but also allows for Primaloft to have relatively good compressibility. If you're the type of person who highly values absolute performance, Primaloft ONE is probably the insulation for you.
-Primaloft Sport is a step down from ONE in terms of warmth. It is also widely used.
-Primaloft ECO is made partially from recycled bottles. This makes it a more earth conscious synthetic insulation, and it is increasingly showing up in products from many manufacturers. The downside to ECO is that it is not as warm as Primaloft ONE or Primaloft Sport.
-Primaloft Synergy, seen in this review on the Patagonia DAS Parka, is a continuous filament insulation made with fibers of differing deniers (thicknesses). Primaloft calls this their loftiest insulation. The insulation less compressible overall, but more durable in the long run.
Arc'teryx uses its own insulations. Coreloft is the short staple insulation used in many of their insulated products namely here the Atom LT and SV jackets. It is very warm, but not quite as warm as Primaloft ONE. ThermaTek, is a continuous filament insulation used in some of Arc'teryx's high end products - in this review it is seen in the Arc'teryx Fission SL. ThermaTek is dipped in a hydrophobic solution for water repellence, and due to its continuous filament construction can be laminated to lightweight fabrics. This makes the insulation very durable and stable within the jacket. Arc'teryx tells us that ThermaTek has a better warmth to weight ratio than their Coreloft, and that its main advantage is its water resistance and ability to stay warmer when wet.
One of the newer players in the market is Polartec Alpha. Polartec, known primarily for their fleece products, is also the creator of NeoShell waterproof breathable fabrics. Polartec Alpha differs from the other insulations in this review because its primary goal is breathability. Products made with this insulation are intended to be worn during activity (in a more traditional light insulated jacket you'll likely overheat and start to sweat profusely if you try to keep it on in high output activities). The major disadvantage to this insulation, is that added breathability comes with reductions in warmth. Polartec Alpha is not nearly as warm as Primaloft ONE, or Coreloft, but it doesn't intended to be either. The Rab Strata is the only jacket in this review with Polartec Alpha.
MontBell has their own insulation as well - EXCELOFT. This uses a combination of fiber thicknesses, 8 denier, and ultra-fine .7 denier fibers. It is a short staple insulation like Primaloft and Coreloft. Mountain Hardwear uses what they call Thermic Micro. This is also a short staple insulation.
Finally, there is wool. Ibex and Smartwool are now using wool as a jacket insulator in some products (as opposed to the usual knitted wool garments). Wool maintains warmth when wet, but can get quite heavy when saturated. In our testing we found the jackets with wool insulation to be heavy for their warmth, and not as compressible as their synthetic insulation counterparts. Wool is however a natural, more environmentally sustainable insulator.
Insulated Jacket Features
A commonly asked question in the retail shop is, "Is this jacket waterproof?" Well, in this review, with the exception of the Arc'teryx Fission SL and the Mountain Hardwear Quasar Insulated, the answer is "No." Having a waterproof shell might sound nice, but in reality this creates a lot of disadvantages as well. Waterproof shells are heavier, more expensive, and less compressible. For the vast majority of applications, having a waterproof shell is not necessary. A more versatile system is to own a standard insulated jacket which you can then layer under a waterproof rain shell if need be. In this review we have listed the shell material for each jacket under the heading "Main Fabric" in the specs chart.
Most jackets will come with a DWR treatment on the outer shell material, which will repel light precipitation. Over time however, the DWR coating will wear off and will need to be maintained. DWR treatments offer light protection from the rain, but will not keep you dry in a downpour.
Outer shell fabrics range in weight. In general, the heavier the shell the more durable it will be. Lighter fabrics make for lightweight, but more delicate jackets.
Some jackets stuff into their own pockets and feature small clipping loop. This is a very helpful feature for multi-pitch rock, ice and alpine climbing since it allows a climber to easily carry a jacket clipped to the harness as they climb to be worn at a belay for warmth. For other applications like hiking, backpacking, camping, or everyday around town you primary packability concern is overall weight and compressibility.
Many of the jackets we tested come in hooded or non-hooded versions, allowing you to make a choice in the matter. What are the pros and cons? Hoods add significant warmth for only a bit of overall weight. They will increase the comfort of the jacket in windy, cold, or wet weather. For these reasons we think that hoods are usually always a plus. Many jackets, like the Rab Xenon and the Patagonia Nano Puff Hoody are very light and packable despite having hoods. If you really only need light insulation, a hoodless jacket will be lighter, less bulky overall in your pack, and will layer slightly easier if you're wearing other hooded layers.
There are two different types of hood designs in this review - hoods with cinch cords, and "fixed" hoods without cinch cords. The warmer, heavier, more winter specific jackets we tested all have the more standard adjustable hood design with one, two, or three (even four!) different cinch cords. The advantage here is a customizable hood fit both with and without a helmet on since you can adjust the hood around the face, front to back etc. If the weather gets really bad, you can really cinch it down and hide away in the hood. Many lighter jackets also have hoods of this design. The other style of hood in this review is the "fixed" hood as seen on the Rab Xenon, Patagonia Nano Puff Hoody, and Arc'teryx Atom LT. These hoods have no adjustment. Rather they have elastic piping around the face creating a snug fit that comes lower over the forehead. Some of these hoods fit better under a helmet than over. Although a bit a silly looking at first, these hoods are more and more common. They are warm, and lightweight.