Synthetic Vs. Down Insulation
The first decision when buying an insulation layer is to decide if you need a down or synthetic jacket. Down is much warmer for its weight and compresses better, but when it gets wet, it will lose its loft, meaning it will also lose its ability to keep you warm. Synthetic insulated jackets are quite a bit heaver at the same thickness and warmth, and they don't compress and pack down as well, but they keep much of their loft when wet. This means that even when wet a syntactic jacket can still retain some of its insulating capability and thus its warmth.
Down tends to last longer, and the feathers themselves allow for more breathability than synthetic insulations. Your average synthetic jacket will lose much of its warmth over 5-7 years, depending on wear, compared with your average down jacket that with equal care can retain its warmth for10-20 years. Down also has a higher resiliency after being compressed than synthetic insulations, so after being unpacked a down jacket will regain its shape more quickly.
Synthetic jackets are more durable when it comes to abrasion. If you climb that last chimney pitch in the dark wearing your synthetic puffy coat and put some holes in it, no big deal. If you put holes in your down coat, the filling will leak out like the first winter snow. That white fluffy stuff that comes from birds also tends to be more expensive.
Hydrophobic Vs. Regular
Hydrophobic down, which is a new technology becoming available on the market is an attempt to solve down insulation's greatest drawback - its vulnerability to moisture. New nano-technology coatings are designed to postpone the down from absorbing moisture and allow it to dry faster once it does become wet. These developments in down are a relatively new technology but should be watched. The potential here is exciting.
But how well does hydrophobic down really work? Would one truly want a hydrophobic over a synthetic? If you get caught in a storm and your jacket gets soaked, how long does it take for the loft, and therefore the warmth, to return? Is this actually beneficial in real-world applications? These are some of the questions that will be answered as these technologies comes into the market and we very much intend to test the limits of various hydrophobic down coatings as they emerge in available products, and are doing so already. What we do know now is that although hydrophobic down does manages a certain degree of moisture better than standard down, it is not an equal substitute for synthetic insulations when soaking wet which is something critically important to think about if you're engaging in activities in which you might get wet.
Another consideration is durability. Down is inherently very durable: able to endure hundreds of compressions. Washing can help restore even old down to close to the performance it had when new. So another question we are beginning to investigate is this: does the hydrophobic coating sacrifice some of down's inherent durability? Water resistant DWR (durable water repellant) shell coatings don't ever last for the full lifetime of a jacket, so how long does a hydrophobic coating last on the down?
We are planning to test standard and hydrophobic down side by side in garments and sleeping bags over the long-haul in order to see if the treatments actually make an observable difference and to investigate if the coatings reduce the durability of the down. Currently OutdoorGearLab is brainstorming quantitative tests using skin temp readings on dummies and thermal imaging that aim to make concrete distinctions between the insulation values of coated and uncoated down. We are looking forward to sharing our findings.
Down Fill Powers
Fill power is perhaps the most commonly misunderstood purchase decision factor. Usually a manufacturer will advertise a "fill power" of 650, 700, 850 etc. These numbers are a reference to the quality of the down insulation used. The number is actually a volume the amount of cubic inches one ounce of down occupies. For example, one ounce of 800 fill power down will occupy 800 cubic inches when compressed by a standardized weight. If you use two ounces of 800 fill on jacket A, and two ounces of 700 fill on jacket B, jacket A with the 800 fill down - will be warmer because it has more loft. However, a jacket may have eight ounces of 850 fill down and yet be of similar warmth to a jacket with twelve ounces of 650 fill down. The jacket featuring 850 fill down has similar warmth but will weigh less, and be more compressible, since it has less down in it. In other words, higher fill power down allows for better warmth-to-weight ratios.
In general there are two primary construction methods:
This method is most common. It is easier and less time-consuming for manufacturers than box baffle construction. The outer material is stitched directly into the inner lining, separating the down in different baffles. This method uses less fabric and is lighter than more complicated box baffle construction (see below), and is less costly. Because of weight, simplicity, and cost, most of the lightweight jackets, and many of the heavier ones, found in our reviews utilize this construction. Although sewn through construction saves weight via the use of less material, it is less warm than box baffle construction because the down is pinched at the seams of the sewn through baffles and thus loft is reduced to zero at each point of baffle stitching. The sewn through baffling prevents the migration of the down (like a box baffle), but due to the simple construction it also reduces the optimum loft of the down, creating "cold spots" at each baffle seam.
The photo below shows three things: 1) How down insulates much better than a cotton hoody (duh). 2) How heat escapes from the seams of sewn through construction. 3) That the found of OutdoorGearLab, Chris McNamara, is actually an alien.
Box Baffle construction is the best method for optimizing the loft, and warmth, of the down fill. As opposed to sewn through construction, in which the outer and inner layers of the jacket are sewn together to create separate baffles, box baffle construction means that each separate baffle is its own three-dimensional cube or rectangle. This means that there is much less pinching of the down at the baffle's perimeter, maximizing the loft of the down, and minimizing cold spots. Jackets constructed this way are usually thicker, warmer, and more uniformly puffy with smoother baffles. Due to the use of extra material, and complexity, box baffle construction is sometimes heavier and more expensive, but offers a more optimized down performance, in terms of pure warmth, than the sewn-through method. Generally speaking, parkas are more likely to feature box baffle construction than lighter weight down jackets.
Some jackets feature both methods of construction. Generally box baffles on the chest and back, and sewn-through baffles on the arms.
The main fabrics (the outer shell and the lining) have an affect on its performance in four primary ways: durability, weight, warmth, and water resistance.
A lightweight model that weighs about 9 ounces usually has only 3 ounces of down. The remainder of the total garment weight is the fabric, zippers, and other various small features like Velcro and cinch cords for adjustability. Jackets with lighter materials are more compressible and lighter.
Different fabrics have different durabilities. Thinner, and lighter, materials are usually more vulnerable to abrasion and snagging. There are many super-light shell fabrics on the market that are rather impressive they allow for the construction of jackets with phenomenal warmth-to-weight ratios. However if you are looking for a down jacket that you can use and abuse for years and years, consider that shell fabric durability may be your primary concern considering that down is itself inherently durable if properly cared for. When researching a jacket you're considering purchasing take the time to note the shell fabric material and it's relative weight compared to other similar jackets. Some jackets, like the MontBell Frost Smoke combine fabrics of different weights and durability in order to keep the total weight of the jacket relatively low while not entirely sacrificing overall durability.
The shell fabric will also affect the warmth of the jacket. You want the fabric to breathe a bit, allowing perspiration to escape. Otherwise the down would wet and lose its loft.
Finally, the shell fabric is what protects the down from the elements. Fabrics with a tighter weave are more water resistant. Although all of these jackets tested here have some sort of DWR (durable water repellant) coating, these wear off in varying degree of quickness.
If weight and pack-ability are your major concerns, consider one of the jackets here with super-light shell material like the Mountain Hardwear Ghost Whisperer or for a warmer option, the MontBell Mirage. If durability is your major concern than consider some of the jackets with slightly burlier shell fabrics like the MontBell Frost Smoke or the Outdoor Research Transcendent.
Intuitively, the thickness of the jacket correlates with how warm it is. But before you buy the thickest jacket available, consider what you intend to use the jacket for. If you want a jacket for alpine climbing, multipitch rock climbing or other such backcountry travel, consider one of the lighter weight, sewn-through, and highly compressible layers such as the Mountain Hardwear Ghost Whisperer, the First Ascent Micro Therm, or the Outdoor Research Transcendent. If you simply want a jacket for wearing around town in cold winters or the occasional car-camping trip, these lighter layers may not be warm enough or durable enough for you. If that's the case check out some of the warmer down jackets tested here like the Frost Smoke, Alpine Light, or Mirage jackets, all from MontBell, or consider purchasing a true parka, which are generally thicker, warmer, and more suited to repeated abuse. Remember that the construction method will also have an effect on your jacket's warmth. As discussed above, box baffles will minimize cold-spots and optimize the loft within each baffle.
Hood or No Hood?
Overall, hoods keep you warmer, especially in windy conditions. Many of the jackets we tested come with both a hood and a non-hood option, with the hooded versions costing slightly more. If you're looking for a down layer to keep you as warm as possible then get a hood. If you often wear your jacket as a mid-layer, consider a non-hooded jacket which will layer a bit easier under your chosen outer-wear which probably has a hood. Keep in mind that not all hoods are designed the same. Some hoods are made to wear over a climbing helmet and are rather big if you don't happen to be wearing one at the time. Other hoods, like on the Mountain Hardwear Ghost Whisperer, and the First Ascent MicroTherm, are designed to be tighter fitting to the face and worn under a helmet. These hoods are good at keeping the cold out and offer a tighter, sleeker profile, while climbing or hiking, but they look a little funny for around town.
Stuffable / Clippable
One of the great advantages of down is its compressibility, many jackets either come with a stuff sack or compress into their own pocket. Jackets that stuff into either a chest or hand pocket and have a clippable carabiner loop are more advantageous for climbing then a separate stuff sack because of the ease with which you can attach the stuffed jacket to your harness. This is particularly nice when climbing multi-pitch routes where you only have a small follower's pack, as it allows the leader to lead with the jacket on their harness and thus have it at the belay, while the follower carries the pack. The other issue with separate stuff sacks is that you have to be careful not to lose it. Take a peek at the photo below to compare the sizes of several jackets stuffed into their stuff sacks or pockets.
Pockets / General Features
Besides the obvious differences in warmth, lighter jackets and parkas also differ quite a bit in terms of pockets and features. Several of the light down jackets here skimp significantly on the features as a means of saving weight, this is noted in the reviews. On the other side of that spectrum are parkas that are designed for expedition use and are full of features intended to make your life easier in the cold. Many parkas ,for example, feature interior mesh drop-in pockets to warm your frozen gloves and water bottles.
This is a subjective thing but can be important to many people. First off, you're best bet is to critically think about what you want to use you down jacket for to what degree is weight and compactness an issue? How warm do I need to be? Once these questions are settled consider the overall style. You will see in out review that the baffle design is different on almost every jacket. Partly this has to do with warmth, but designers also use things like baffle shape to construct the look of the jacket as well. we have also noted the number of color options for each jacket.