What is the Fill Power and Down Weight of your Down Jackets?

down jacket

Whether you’re navigating a snowy slope, heading to the office, or simply enjoying the winter chill, staying warm is paramount, not just for comfort but also for safety. However, with a plethora of down jacket options available, finding the perfect one can be daunting. In this comprehensive guide, we’ll delve into what down insulation is, its importance, and key factors like fill power and weight that are often overlooked. We’ll also decipher warmth-to-weight and down-to-feather ratios, helping you understand how to gauge the warmth of a jacket. Don’t let cold weather deter you from outdoor adventures or daily routines. Use the insights provided here to make an informed decision when purchasing your next down jacket.


What makes down jackets so special?

Down is a type of natural insulating material that is commonly used in down jackets. It is the layer of fine feathers found underneath the tougher exterior feathers of ducks and geese. These feathers are extremely light and fluffy, with a three-dimensional structure that allows them to trap air and provide excellent insulation.

One of the main reasons why down is used in down jackets is its exceptional thermal properties. The lofty structure of down creates a high-loft insulation that keeps heat in and cold air out. This makes down jackets highly efficient at retaining body heat, even in extremely cold temperatures.

Another advantage of down is its ability to compress and retain its insulating properties. Unlike synthetic materials, which tend to become compacted over time and lose their insulating abilities, down maintains its loftiness even after repeated compressions. This makes down jackets highly packable and lightweight, perfect for outdoor activities or traveling.

Down also has excellent breathability, which means it allows moisture to escape from the body while keeping the wearer warm and dry. This is important as it helps regulate body temperature and prevents overheating during physical activities.

Additionally, down is known for its durability. With proper care, a good quality down jacket can last for many years. The natural oils present in down feathers help to repel water and keep the insulation dry, making it resistant to moisture and mold.

Furthermore, down is a sustainable and eco-friendly choice. It is a byproduct of the food industry, as the feathers used for down jackets are harvested from ducks and geese that are raised for meat consumption. By using down as an insulation material, we are utilizing a renewable resource and reducing waste.


What is fill power for down jackets?

The loft of a down product, known as fill power, is a key indicator of its quality. Fill power measures how fully the down clusters expand, determining its ability to provide insulation. This rating is calculated by assessing how many cubic inches an ounce of down can cover at its maximum loft. For example, a fill power rating of 600 signifies that one ounce of down can cover 600 cubic inches. The measurement process involves placing the down into a Plexiglas cylinder and compressing it slightly with a weight.

It’s important to understand that fill power is measured differently in the United States and Europe due to variations in cylinder specifications. In the U.S., the cylinder has a diameter of 241 millimeters and weighs approximately 68.3 grams, while in Europe, it is larger, with a diameter of 289 millimeters and a weight of about 94.25 grams.

Fill power ratings typically range from 300 to 900 and above. While the most common down products fall within the 400 to 500 range, these are often considered low quality as they are sourced from immature geese and ducks, resulting in smaller down clusters. For those seeking high-quality down fill jackets, it’s advisable to look for a fill power rating of at least 550, ensuring superior warmth and comfort.


What is fill weight for down jackets?

When it comes to down jackets, understanding both fill power and fill weight is crucial. Fill power represents quality, measuring the loftiness of the down, while fill weight indicates quantity, referring to the actual weight of the down material used. While many brands focus on promoting high fill power, the significance of fill weight should not be underestimated. Fill weight plays a vital role in determining the warmth and compressibility of the jacket, aspects that are essential for outdoor enthusiasts.

As explained by the Down and Feather Company, fill weight determines the softness, firmness, and compressibility of the product. The ability of down jackets to compress without damage is particularly valuable for outdoor activities where space is limited, such as backpacking. However, it’s important to note that heavier down jackets may have reduced compressibility, impacting their suitability for certain situations.


What is the down to feather ratio?

The down-to-feather ratio plays a crucial role in determining insulation quality, often represented as ratios like 70/30, 80/20, or 90/10, denoting the percentage of down to feathers in insulation material. A higher first number indicates superior-quality and typically more expensive products, offering better insulation. For instance, a 600 fill power down jacket with an 80/20 down-to-feather ratio provides superior warmth compared to a jacket with a 70/30 ratio. Unlike feathers, down clusters consist of thousands of tiny fibers and air pockets that efficiently trap heat, ensuring enhanced warmth and comfort in jackets, sleeping bags, and duvets.


Which makes jackets warm?

When choosing a down jacket, it’s crucial to find the right balance between fill power and down weight to ensure maximum warmth. Consider both factors carefully. For example, a jacket with 500 fill power and 10 oz. of down will provide more warmth than an 800 fill power jacket with only 5 oz. of down. Similarly, given equal down weight and down-to-feather ratio, an 800 fill power jacket will offer superior warmth compared to a 500 fill power jacket. Additionally, an 800 fill power jacket requires less down to deliver the same level of warmth as a 500 fill power jacket. Some top down jacket brands like Tanboer prioritize high fill power without compromising on down quantity in their jackets. Unlike many other brands, Tanboer discloses both the fill power and down weights of their men’s, women’s, boy’s, and girl’s coats. Performance athletes, such as hikers, climbers, and skiers, prefer high fill power jackets like those rated 800 fill power due to their lightweight yet warm nature. To simplify understanding the relationship between fill power, down weight, and down-to-feather ratio, many companies use the Clo value. Clo measures the insulation value required to maintain comfort in specified conditions, with higher Clo values indicating warmer products. For instance, a jacket with 550 fill power and 1 oz. of down has a Clo of around 0.7, while one with 800 fill power and 1 oz. of down boasts a Clo of approximately 1.68. Keep in mind that according to Adventure Poet, winter temperatures from -4º to -40º F require clothing with a Clo value of 4 or higher for adequate warmth.



Fill power and down weight serve as the horsepower and torque equivalents for insulation, with higher fill power indicating superior quality down and greater compressibility for enhanced warmth. Combining high fill power with a substantial fill weight ensures maximum insulation. This guide simplifies the complexity of down jacket specifications, highlighting the significance of factors like fill power, down weight, and down-to-feather ratio. In cases of confusion, prioritize garments with higher Clo values for superior warmth. Additionally, consider the distribution of down within the jacket, whether through sewn-through or box baffles, as it influences overall warmth consistency. Prioritize safety in cold temperatures by selecting a high-quality down jacket that offers protection and prolonged comfort. Stay warm and continue exploring confidently with our comprehensive insights.