When buying a down duvet or pillow, you may notice a measurement on the label which indicates the product’s fill power or loft. In this blog entry, we’d like to explain to you in more detail what a down product’s fill power means and what exactly this measurement says about the duvet or pillow’s quality.
In addition, we'll present the various types of down filling and explain their differences. We’ll show you which type of down keeps you warmest and how to find the right product for your bedroom.
What does fill power mean for down?
If you’re on the market for a duvet with down filling, there are a few points you should consider before making your purchase. In addition to other factors to take into consideration, like the type and origin of the down, its fill power also plays a decisive role.
A down product’s fill power, also known as loft, indicates how well the down insulates. You can therefore use this measurement to determine how high quality your down bedding is. This value is given in 'cuin,' which is an abbreviation for 'cubic inches'. One cuin is approximately 16.38 cubic centimetres.
The cuin value is higher when the down has a greater air cushion and provides better insulation. Accordingly, a lower cuin value means the down creates a smaller air cushion and has a lower insulating capacity. Air cushions are important when it comes to retaining warmth underneath the duvet and keeping out the cold.
How is the fill power of down products determined?
To determine an item’s fill power, experts apply a certain amount of pressure to the down and then measure how high the volume is. To be more precise, the measuring process involves filtering out one ounce (which corresponds to 28.34 grams) of down and pressing the clusters for several hours in, for example, a Plexiglas cylinder.
When the pressure is removed from the down, how far the down clusters then expand is measured. The height and width of the down mass determines the volume and insulating force.
A down product’s fill power is an important factor in deciding on the right bedding or even outdoor clothing. If you are looking for a duvet which will keep you warm, you should choose one with a higher fill power. If you are looking for bedding which will keep you cool, you can choose either a duvet with a lower fill power or a different material.
How is the fill power indicated on down goods?
As stated above, the terms “fill power” and “loft” are used in English-speaking countries and the measurement is given in terms of cuin. The terms “Bauschkraft” and “pouvoir gonflant” are used in German and French-speaking countries, respectively, though German manufacturers sometimes use the English term for their bedding, as well.
What does loft or fill power actually mean?
Before we analyse the meaning of fill power in more detail, we should first take a look at the structure of a down cluster. If you take a closer look at it, you’ll notice that it has a core or shaft and radially shaped barbs that are particularly soft to the touch.
Air pockets form between the individual down barbs. If the down has very long barbs and many evenly spaced barbicules, this results in a higher fill power. Since down is incredibly light, half a million to a million down clusters are needed for one kilo.
The higher the fill power, less down is needed to provide the same insulating power. This is why you can have light blankets which are nonetheless just as warm. Down duvets with low loft are heavier because more down is used.
How does down attain high loft or fill power?
One factor we've already mentioned is the size of the down clusters. Very young geese have smaller down clusters than adult geese; their down thus also has lower fill power. The second factor is the length of the barbs. Longer down barbs equal superior insulation.
The third factor is the homogeneity of the down. This indicates how regularly the barbs are arranged around the core and how uniform the length of the barbs is. A high degree of homogeneity translates to higher fill power.
A down cluster can always return to its original shape, no matter what amount of pressure it is exposed to. That said, down duvets should be washed properly; using the wrong type of detergent can cause the down to clump together. Be sure to read the instructions carefully before washing your down products.
What is the difference between duck and goose down?
The first difference between duck and goose down is the size. While the average duck down cluster is about 1.5 cm in size, goose down is about the diameter of a one euro coin. This means that goose down is somewhat larger.
For this reason,goose down duvets have a higher fill power and thus also provide superior insulation. This is also reflected in the price, as goose down is usually more expensive than duck down as a raw material.
So which type of down is better? Duck or goose down? The answer depends on how warm you like to sleep at night and where the ducks and geese are from. As a general rule, goose down has a slightly higher fill power and keeps you warmer. But ducks raised in a cold environment like Eastern Europe are equipped with bigger and thicker down and feathers to protect them from the elements, which is why we source our down exclusively from this region. This keeps the difference in isolation from being too great, so the final decision comes down to your personal preferences and budget.
What is the warmest type of down?
The warmest down comes from the eider duck, which is native to the Arctic coast. They are the softest and lightest down in the world. Duvets filled with this type of down have a fill power of 800 cuin or more.
Of course, these duvets are also among the most expensive down products on the market. Moreover, at normal bedroom temperatures, an eiderdown duvet is not usually needed.
Down duvets at Zizzz
We offer high-quality and fairly-priced duvets and pillows made from fine duck down. The down for our filling is ethically-sourced and is DownPass certified. The loft of the down used in our bedding is 575 cuin and we only use down which comes from Europe. Our goose and duck down products are made in Switzerland and Germany, respectively.
If you’re looking for an alternative to down duvets, we also have something for you here, namely our breathable Swisswool duvets. Swisswool is a patented filling material made from pure virgin wool from happy sheep raised in the Swiss Alps, which has been reinforced with plant fibres to make it machine washable. Wool is temperature-regulating and helps to keep your body at a comfortable temperature all year round.
Conclusion - Down fill power
A down product’s fill power indicates how well a down product can insulate. A high fill power means larger down with evenly spaced down barbs and thus larger air cushions. If you are looking for a particularly warm duvet, you should choose one with a high fill power.