Last Updated: December 8, 2023
Down Fill Power Ratings (Everything You Need To Know)
Wondering about the numbers on the labels inside your down jacket?
These figures provide information about the jacket’s insulation quality and warmth if you understand their meaning.
They indicate the
- type of down
- down fill power
- feather-down ratio
This guide will clarify these terms and help you discern the best down jacket.
Table Of Contents Show All
Summary
- Goose down is better than duck down at keeping you warm
- Fill power number indicates the amount of space one ounce of down occupies
- The higher the fill power, the warmer the type of down
- Weight of down insulation is also important
- Down to feather ratio is also important (look for 80-20 or 90-10)
- The perfect down jacket for you should be warm enough for your area
Goose Down Vs. Duck Down
Image Courtesy of Thomas Brueckner
The first thing you need to look for is whether a jacket is insulated with goose down or duck down . That is one of the most important things since it also impacts:
- fill power
- overall insulation
- down-feather ratio
Duck down is what you normally see in most jackets. It’s easy and cheap to produce.
The majority of brands use duck down in their jackets, especially the more affordable ones.
However, it is also of lesser quality than goose down. That is because clusters of goose down tend to be larger than clusters of duck down. That results in
- higher fill powers
- better quality
- more durability
- lighter clothing
If you have the same amount of clusters of goose and duck down. You would need more duck down.
This is because the clusters are not as large and they cover smaller amounts of space. There will be holes in the insulation – empty space between the clusters, areas that are not covered with insulation.
Insulation is meant to trap your body heat. When a jacket has less insulation and heat escapes through – and you don’t feel as warm as you should.
Goose down is more expensive to produce, and jackets with goose down are more expensive as a result. So, it is not used as often.
However, there are instances in which duck down is actually the better option – high-quality duck down obviously performs better than mediocre goose down.
Fill Power Of Down
Fill power is directly related to the size of down clusters – that’s why goose down generates higher fill powers than duck down.
It measures the size of space one ounce of down is able to insulate when it reaches maximum loft (or fluffiness in layman’s terms). Larger clusters are able to trap more air, and are better at retaining your body heat.
Definition Of Down Fill Power
Down fill power is a measure of how many cubic inches 1oz of down takes up in a cylindrical tube.
Fill power can be identified by the number that accompanies it. That number usually ranges from 350 to 900, and it indicates how much space the down occupies. This number is found using a standardised test, so the values can be easily compared.
Let’s take an example. If you want 700 cubic inches of space, it will be filled by
- 1 oz of 700 fill power down
- 2 oz of 350 fill power down
When you look at average down jackets you can buy today, you’ll notice that most of them are insulated with 550-650 fill power down. That’s kind of like the best middle ground – it’s
- high quality
- high loft
- not too expensive to produce
Jackets that are insulated with 700-900 fill power down are usually warmer, but they are much harder to find. And these are usually jackets designed for extreme weather conditions.
If you are looking to get a warm winter jacket, look for anything with 550 fill power and above. Anything lower than that won’t really be warm enough for sub-zero temperatures.
900 fill Power Jackets
900 fill power goose down is the “golden standard” – as good as it can get. But not a lot of brands offer jackets with this insulation, and especially the cheaper ones.
North Face is one of the few that makes these jackets, but they tend to be really expensive. However, if you’re looking for the warmest jacket money can buy, that’s the number you should be searching for.
Weight Of Down Insulation
Most manufacturers won’t tell you the amount of insulation in their jackets – they’ll usually tell you the fill power, and potentially the down/feather ratio, but they often skip weight. That’s because it actually plays a really big role in keeping you warm.
Maybe you’ll see a jacket that’s insulated with 700-fill power down for $50. And that is too good to be true – what the manufacturer isn’t telling you is that there’s probably very little insulation in that jacket. Meaning that it is not completely insulated and it has cold spots, and you won’t actually be warm in it.
Which Is Warmer?
If you have two jackets, one is insulated with 100 grams of 550 fill power down, and the other one with 60 grams of 700 fill power down. Which one is warmer?
The first one. Let’s just look at the numbers here – 100 grams is 3.5 ounces & 60 grams is 2.1 ounces. That means that the down in
- the first jacket takes up 1925 cubic inches
- the second jacket takes up 1470 cubic inches
So, the first jacket is actually significantly warmer than the second one – more insulation means fewer cold spots and a higher warmth level.
Check The Tags For Down Weight
It’s not just about the fill power. The actual weight of the down in a jacket plays a huge part as well, and that’s one specification you should always be checking. If you are looking at a jacket in-store, you should be able to find that info on the tags. If you’re looking at it online, you can always contact the brand and ask them directly.
More Insulation is More Expensive
However, keep in mind that jackets with more insulation are usually more expensive, especially if they are insulated with a really high fill power down.
Down-Feather Ratio
Definition Of Down-Feather Raion
Down to feather ratio is the amount of down versus the number of feathers in a jacket. The higher the amount of down, the warmer the jacket.
High-quality jackets should have at least an 80-20 down-feather ratio because down does a much better job at trapping air than feathers, which have a quill.
In many ways, feathers are “just fluff” in comparison to down – which is to say, far less useful at keeping you warm. According to Wikipedia, feathers only have a fill rating of 300 at their best.
90-10 ratio is as good as it gets, and that’s what you’ll see in high-quality brands like North Face or Moncler. And most of the good brands will actually tell you the ratio of down-feather in one of their “about us” pages because the ratio is the same in all of their jackets.
If a manufacturer avoids telling you this in one of their jackets, then you can assume that it is lower than 80-20.
This doesn’t mean the jacket is useless – I have several 70-30 jackets that are great for late fall and early winter. It all depends on the area you live in and how cold it gets there. In my experience, 70-30 jackets are great for temperatures that don’t drop below 4-5 degrees Celsius. But for anything colder, you will want more down in your winter jacket.
Distribution Of Down Insulation
A jacket can be insulated with 100 grams of down, but what if all of that insulation covers only its body? The sleeves and the hood won’t be nearly as warm as the rest of the jacket.
A jacket that has 90 grams of down, but which is entirely insulated (including the sleeves and the hood), will be warmer than a jacket that has 120 grams of down but only in the body. That’s because your entire body will be warm and cozy, and your body heat will stay inside the jacket.
But if that is not the case, even if the jacket is insulated with 900-fill power down, you won’t be as warm – eventually, your arms will start to feel cold, and that is a feeling that can easily spread.
Some brands will tell you that these parts of their jackets are filled with down – Canada Goose is one of those, and the first one that comes to mind. You should always look for this info in the descriptions of the jackets. And if you’re not sure, don’t be afraid to ask questions – after all, you should know exactly what you are getting for your money.
Finding The Right Down Jacket
It’s actually not as simple as “oh let’s just look for the highest fill power with the highest amount”. Being too warm is a real issue – one that can render your brand new, ridiculously expensive jacket useless.
Cold Winters
You need to consider how cold your area gets in the winter. If the temperatures are often below zero, then you should be looking for higher fill powers,and generally, jackets that are heavily insulated. Canada Goose actually has a really helpful rating system for their jackets, as they tell you exactly the temperature range in which they are designed to be worn.
Mild Winters
But if you live in areas where winters are milder, don’t get ahead of yourself and buy a super warm jacket – you’ll rarely wear it. If you want something you can wear every day, look for a jacket with lower fill powers, or high fill power but a lower amount of insulation.
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About the Author Anna Timbrook
Anna is the co-owner of expert world travel and can't wait to share her travel experience with the world. With over 54 countries under her belt she has a lot to write about! Including those insane encounters with black bears in Canada.
