What Does Down Fill Mean?

When looking at jackets there is the style that you have to look at, but you also have to consider how warm the jacket or coat is going to keep you. Depending on the type of jacket or coat, one of the measurements for warmth is down fill power. This looks at the down content of the jacket and tries to measure how warm it will keep you.

So what does down fill Mean? In this article we will talk about what down fill is. We will also talk about what down fill means. Lastly, we will cover down fill power. This way after reading this article you will know everything you need to know about down fill and what it is. That way the next time you are picking out a coat you will be able to pick the one that is best suited to you and your needs.

What Does Down Fill Mean

What Does Down Fill Mean

What is Down

Before getting into what down fill power is, it is important to first understand what down is and why we use it. Down is a fluffy material that comes from a bird. The most common type of down used comes from ducks and geese. The down is the soft plumage or undercoat of the feathers near the belly. The more mature the bird that the down comes from the greater the loft and higher fill power. We will cover these two concepts farther down, so stick with reading this article to learn what is meant by loft and fill power.

What does Down do

Before getting into what loft and fill power is though, we are first going to look at why we use down. Down is used as a type of insulation when it comes to coats and other things. The purpose of insulation is to keep you warm or more specifically to hold heat in. You use insulation in your home to keep the hot air out in the summer and keep the warm air in during the winter. The same concept applies to down in coats and jackets. Standard thermodynamics states that heat will always move from a hotter region to a colder region to achieve equilibrium. Normally your body is the warm region and the outside air is the cold region. Down will trap your body heat and keep it in near your body.

How is it used

So, you may be wondering how down is used in a jacket. Well, during production it is formed into clusters. The clusters are formed together by crisscrossing the fibers of the down. It also develops air pockets when the clusters are formed. The pockets of air allow for the down to trap heat while also allowing the jacket to breath. Since it is so compact it down fill offers great warmth to weight ratio. It also resist damage form compression allowing you to squeeze a lot of down fill into a small space. These factors is why down is such a great insulator and why some consider it the best insulator known to man.

What is fill power

So, now that you know what down is we can move onto the key three factors that you need to know about down. They are what is down fill power, what is fill weight, and what is down to feather ratio? The first one of these that we are going to cover is what is down fill power? The fill power when it comes to jackets is a measure of the loft of the down. In simpler terms fill power describes the quality of the down. The top quality loft occurs when the down is able to expand all the way. The down fill power is a calculation that looks at how many cubic inches an ounce of down can cover at maximum loft. So that means that a down with a rating of 300 can cover 300 cubic inches per ounce. The test is done by putting the down in a cylinder and compressing it with a weight.

One important thing to remember is that the test is done differently in the United States, than it is done in Europe. This means that depending on where the coat was produced the rating will be different. The rating can range from 300-900. However, even though there is that wide range most down rates between 400 and 500. This is low quality however and the down comes from immature birds. If you want a higher quality jacket you should find one with a fill rating of at least 550. This way it will be warmer and more comfortable.

What is Fill Weight

The next idea we will look at is what is fill weight? The answer to this should be pretty simple. If fill power is volume, then fill weight is weight. In other words fill power is quality, while fill weight is quantity. The measurement is normally given in ounces, so if you find a jacket with a fill weight of 10, then there is 10 ounces of down in the jacket. The fill weight is important because it lets you know how soft the jacket will be as well as how well it will compress. These things are important because the more down a jacket has the harder it will be to stuff it into a backpack if you need too.

What is down to feather ratio

The last thing we are going to look at is what down to feather ratio is. If the name hasn’t clued you in, it is the amount of down in the product compared to feathers. The number is normally given as a fraction and can look something like 75/25. The first number represents the percentage of down, while the second represents the percentage of feathers. Normally you want to try to find a product with a higher first number. This is because it should be of better quality. That is because down is a much better insulator than feathers.


So, now that you know what the three key factors actually means, how can you determine how warm a jacket will be? Well, this can be hard because fill power and weight can vary each other if there is a difference from one jacket to the other. Normally though more down equals more warmth. This is not always the case though if the fill power is widely different. Also, the higher the fill power the warmer it will be. For example if the weight is the same a jacket that has a fill power of 500 will be warmer than one of 300. The key is to try to find a jacket with high fill power and as much down as you need for weight.


So, now you know everything you need to know about what down is. You also know what down fill power is, what down weight is, and what the down to feather ratio is. The next time you are shopping with something that has you should be able to make an informed decision on what is best for your needs. Just remember that the more down the better, especially if it is top quality down.

Tom Chandler

"When your hands hit the floor, they get cut up. When mine hit the floor, they slide with ease"

Click Here to Leave a Comment Below 0 comments