About Down is courtesy of St. Geneve
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No other insulator exists that is as effective as good quality down. Not even close.
It is not the down itself that actually does the insulating, it is the
tiny air pockets trapped by the down fibers. The smaller and more
numerous the air pockets, the more efficient is the insulation, as
convection currents that carry heat away are eliminated.
Resiliency is the ability to be compressed and then spring back to the
original volume. No other material regains its "Loft" like down.
Obviously, if a material does not spring back to its original volume,
it loses a considerable portion of its insulating power. Quite simply,
thickness is directly related to insulating power.
Down Breathability: Down
is superior to other materials in its ability to "breathe". It actually
allows water vapour to pass through it, without letting warmth escape.
This means that the sleeper will not get clammy, because the down has
"wicked" away the moisture that would be trapped by other materials.
Considering that a person can perspire up to a liter (1/4 gallon) in a
night, you can see why a down duvet can be cooler in the summer than
Down Longevity: With
proper care, Down will outlast any other insulating material. We have
recovered quilts up to a hundred years old, and the filling was still
in good condition.
To achieve the same insulating power, far less down by weight is
required than any other material. Therefore, an individual will enjoy a
much more restful sleep, since he is not weighed down and restricted in
All the things that down does; insulation,
longevity, breathability, and lightness, are far more pronounced with
high quality, large cluster mature downs.
65 year old Goose Down
Down is an incredible insulator
What makes one down better than another? If it is a batch of large
mature clusters, it will be warmer in winter, cooler in summer, and
last decades longer. High quality down fills a larger space and has
more insulating power than the same weight of a lower quality. Small
down clusters have poor filling power and tend to collapse after two or
three years, because the filaments are small and fragile. There are
different reasons for variance in down cluster size.
In general, goose down is superior to duck down simply because it
usually comes from a larger bird. But more important than the kind of
bird, it is the bird's size and maturity that determines the quality of
its down. So in fact, a high quality duck down is better than a low
quality goose down.
There are big differences even in one type of down. For example, mature
White Goose Down will look like the large down plumule in the image
(top right), in actual size. It has an extraordinarily high warmth to
weight ratio. A duvet filled with this down will be very light and
warm, and will last for decades.
On the other hand, an immature White Goose Down will look like the
small down plumule in the image (bottom right) in actual size. It will
not fill a duvet well. Even if there is a lot more of this down by
weight, it won't be as warm.
Mature down traps more air, puffs up more, and breathes better than
lower quality immature downs. Since it takes less weight of a high
quality down to fill a duvet, the best duvets are also the lightest and
An immature bird will only produce immature down: a low quality down
that won't insulate and won't last. A mature bird will produce down in
various stages of development, because a bird is constantly growing new
down and feathers. So from a single bird, there will be very large,
mature plumules, as well as medium, and small immature plumules.
When this type of down is processed in a "wind tunnel separator"
(diagram shown above), the large feathers fall out first because they
are heavy, then medium feathers, then small feathers, then large down
plumules, and finally the smallest plumules get collected at the very
end of the tunnel. These small plumules are of much less value and are
sold for mass merchant, low quality down bedding. The large plumules
have the greatest value, andare used to fill high quality down bedding.
There are four aspects to consider in rating the quality of down. They
are all very important in determining the insulating power of a given
quality, and the size of the cluster. These aspects include: a loft test; the density, the cling, and cleanliness of down. All these are a reflection of the overall quality of down.
Loft or Fill Power
Down Loft is the number of cubic inches one ounce of down will fill under
specific conditions of temperature, humidity, and load. (This can be
artificially increased by chemical treatment and steam, but this won't
last very long.) Essentially, the larger the bird, the larger the down
clusters, and therefore the higher the loft.
The illustration below shows 1 oz each of different quality downs in
tubes. They vary from 300 cubic inches per oz; which is a typical mass
merchant bargain white goose down, up to 800 cubic inches per oz, which
our top quality downs achieve.
A loft test is done in a plexiglas cylinder of a standard size, under
exacting conditions of specific temperature and humidity, with a sample
of precisely one ounce of down. There is a disc of a specific weight
that sits on top of the sample to simulate the load that the covering
fabric exerts in a finished item.
very wary of claims for lofts exceeding 900. Geese do not grow that
big! Just as there is no 32 carat gold, there is no such thing as 1000 loft down.
The density of down describes how dense the fibers of the down are in
its center. The down actually develops microfilaments on the strands of
the down cluster. The more of these tiny fibers there are, the smaller
the air pockets that will be trapped, and the better the down will
insulate. This is affected more by the age of the bird. High density is
only found in very mature downs. Note that the loft of these two downs
will be the same, but the down in image 'B' will insulate better than
the down in image 'A'.
"A" is a large down cluster that has not yet developed high density.
"B" is from a well matured bird, and has developed a high level of density.
is found when tiny hooks develop on the filaments of a down cluster.
These hooks will catch other down clusters to make a more even layer of
insulation, and as large pockets of air are filled in and eliminated,
the insulating power goes up.
A down with a lot of
cling will also stay in place on top of the sleeper, rather than
shifting to the lowest parts of a duvets chamber. Cling is either
species specific, as in genuine Eiderdown, or it is found only in very
mature downs. In general, as the size of the bird increases, so does
the loft of the down. As the age or maturity increases, so does the
density and cling. This is why the best down comes from much older
birds. They have grown up to be large, and then with further aging,
have developed completely mature down. It is expensive to maintain
birds well into maturity. Since it is expensive to process down with
high clinging ability, the very best down is very expensive, yet
The Down Association of Canada
is a non profit organization devoted to maintaining quality standards
for down and feather products. Members are obliged to adhere to strict
standards under government labelling and advertising regulations.
Members products that meet these standards are entitled to carry this
The principals of St. Geneve have been
closely involved with the Down Association of Canada since its
inception, and were instrumental in bringing the hang tag program into
St. Geneve's down and feathers are so clean that they are guaranteed hypoallergenic
All St. Geneve down is cleaned according to the ZURGUARD standard. St. Geneve Down down is so clean that we confidently guarantee our down products to be
hypoallergenic or the item can be returned after a period of three
months after the date of purchase. (The return period is for three
months as we have no control over the ongoing household environment.)