Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Q&A

Different kinds of Down: comparing insulation

+1
−0

There's many different kinds of "down" filling: "100% down" must legally be only down, while "down" can be any mixture containing down.

Then there's "fill power" ranging from about 400 to 1200, which basically measures how resistent the feathers are to crushing by weight. Higher "fill power" provides more insulation and is significantly more expensive.

Is there any quantitative data about just how much the thermal insulation ability VARIES from the "worst" down to the "best" down? In other words, is it possible that spending 10X as much $$$ on high-end down can make a significant difference in insulation, or is it negligible?

History
Why does this post require attention from curators or moderators?
You might want to add some details to your flag.
Why should this post be closed?

This post was sourced from https://outdoors.stackexchange.com/q/3835. It is licensed under CC BY-SA 3.0.

0 comment threads

2 answers

+0
−0

The primary advantage of higher fill power down is that it is warmer per ounce (or gram) than down of a lower fill power.

If you had two nearly identical sleeping bags: same shell material, same weight of down, but one had 850 fill power down and the other had 700, the 850 fill power would be about 3˚F warmer.

More insight into this and backing for my results can be seen at Down Fill Power Impact on Quilt Temp Rating.

History
Why does this post require attention from curators or moderators?
You might want to add some details to your flag.

This post was sourced from https://outdoors.stackexchange.com/a/3907. It is licensed under CC BY-SA 3.0.

0 comment threads

+0
−0

Fill power doesn't measure crush resistance. It measures the inverse of density, in units of cubic centimeters per gram or cubic inches per ounce.

Insulation doesn't depend on fill power. Insulation simply depends on thickness. However, a higher fill power allows you to achieve a greater thickness while carrying a given weight on your back.

Fill power is measured when the down is puffed up, not compressed. When it's compressed, it gives very little insulation. For this reason, the part of your sleeping bag underneath you is extremely ineffective at keeping you warm. This is why people use sleeping pads, and some people use down blankets instead of sleeping bags.

Because insulation depends so strongly on the amount of compression, it's not possible to say in general that x centimeters of (uncompressed) down will provide y amount of insulation. For example, a down jacket will not be compressed as much as the bottom of a down sleeping bag in normal use.

It also depends on the wind. In a strong wind, there is a certain amount of difference in comfort between a thick layer of down and no layer of down. In totally still air, this difference is much smaller. Essentially all the down does is to provide you with a still layer of air, preventing convection. If the air is completely still anyway, you don't need the down for this.

History
Why does this post require attention from curators or moderators?
You might want to add some details to your flag.

This post was sourced from https://outdoors.stackexchange.com/a/3948. It is licensed under CC BY-SA 3.0.

0 comment threads

Sign up to answer this question »