When purchasing a new down jacket, there are many factors to consider. Known, almost universally, as one of the best insulation materials for jackets, it is no surprise that down jackets are expensive and popular. But its popularity begs the question of just how warm do ultralight down jackets actually keep you? Before we go into this question, we must first ask, how does down insulation work?
Characteristics of Down
Logically, it might seem to make intuitive sense that the more material that there is, the better it insulates. In fact, the more material the jacket contains, the heavier the jacket is. So how does an ultralight down jacket compare to heavier jackets with other insulation? The answer lies in the down.
Down is a great insulation material. It is nature’s way of keeping animals such as ducks and geese warm. What it does is that it traps cold air in its tiny air pockets, creating an effective thermal layer and keeping you warm on the other side of the jacket. There are a few measures of insulation of how much down there is.
This is called the “down fill weight” and the “down fill rating.” The “down fill weight” essentially measures the total weight of the down in the jacket. The “down fill rating” is a quality metric. It refers to the volume, in cubic inches, that one ounce of down fills. Looking at these two metrics allows you to compare down jackets to each other.
Essentially, what down excels is providing a great fill rating compared to other synthetic materials. Essentially, there are more tiny air pockets in the down than any of the other synthetic materials used by pure weight. For example, an ounce of down insulation would provide better insulation than an ounce of synthetic material. While newer synthetic materials have provided similar scores to down, they have yet to completely surpass it.
Down is a great insulator. But there are other reasons that make down’s reputation as one of the best materials for insulation; it is very packable. Its packability makes it easy to take when travelling. You can stick it in any open space. However, it is important to note that it is a poor insulator when compressed.
Despite its great features, there exist some problems with down. For example, untreated down does not perform at its best when wet and takes a long time to dry. For that reason, it’s important to know where the jacket will be used. If you know you’ll be wearing the jacket in the rain, it would be wise to invest in a water repellent down jacket. These jackets are 30% more effective in insulating heat while wet and dry 60% faster.
The construction of the jacket also matters. For example, have you wondered why jackets usually have lines of insulation running through them? Why are they in that pattern?
In short, this way of construction creates pockets of down. This method reduces the jacket’s weight and henceforth, its cost. This makes it practical for ultralight jackets created for cool temperatures. However, for jackets that are meant to be worn in colder temperatures, there is an alternative sewing pattern. The problem with the traditional sewing pattern is that it creates cold spots where there is no insulation. The alternative sewing pattern creates boxes. While this is more costly and adds weight, it also eliminates the cold spots.
Conclusion: How Warm Do Ultralight Down Jackets Actually Keep You?
Down is known as one of the premium insulators for its natural insulation ability, lightweight, and portability. However, when purchasing an ultralight down jacket, there exist other factors that must be considered. While being a down jacket will still make it an effective insulating jacket, it is not a good idea to buy an ultralight down jacket for extremely cold temperatures.
For that reason, it is important to look at the sewing pattern of the jacket you will be purchasing and look at the “down fill weight” and “down fill rating” scores. Furthermore, if you live in a climate with a lot of precipitation, it might be worth it to invest in a water repellent down jacket or go for a synthetic material altogether.
Nevertheless, down jackets are pricey. But that price is often justified by the benefits that it has over jackets of other insulators.
Written by David Chu