Down or synthetic insulation?

You’re starting your first winter project and not sure which type of insulation to choose? In this article, you’ll learn everything you need to know about synthetic and natural insulation to make the right choice.

How does insulation keep you warm?

The common goal of every type of insulation is to trap and retain heat. Clusters of down create millions of pockets that hold warm air, allowing for incredible compression and warmth at a low weight.

Manufacturers of synthetic insulation try to achieve the same effect using clusters of polyester fibers.

List of pros and cons

First, a brief comparison for those who want to decide quickly and get started with sewing. For the curious, we have described all the details and specifications below.

What should you consider when choosing down for your project?

Once you’ve decided on down, what’s next?

Polish down is considered the best in the world. However, just like in any market, you can find down of both lower and higher quality. There are several parameters that indicate top-quality down.

1. Down loft (resilience)

This is the most important parameter we should consider. Its value indicates whether all subsequent criteria are met. Fill power is the most commonly used measure of down quality. Fill power determines the ability of down to expand after being previously compressed in a special piston.

It is expressed in cubic inches per ounce (in³ / oz) – CUIN. For example, a value of 650 cuin means that 1 ounce of goose down (28 g) expands to a volume of 650 cubic inches.

600-650 is considered as a good quality
700 – 750 is considered as a very good quality
800 – 950+ is considered as a perfect quality

2. Geese or ducks down?

Duck down is generally cheaper, but it is also of lower quality. One of the reasons is the odor. In both cases, down can be sourced ethically and in the same way, but the results differ. When separating down from duck feathers, some duck fat may remain on the feathers/down, which can cause an unpleasant smell in your clothing or sleeping bag. This odor can persist even after washing. Goose down, with a few exceptions of rare duck breeds, is also more resilient, and consequently has better thermal insulation properties. Blends of both are often used to achieve a lower price while maintaining better qualities than pure duck down. If price is not a concern, the best choice is 100% goose down.

3. Pure down or a down-feather blend?

Feathers, meaning goose or duck feathers, are again less resilient. This means they have lower thermal insulation properties. A blend can also be used to lower the cost while achieving better quality than using feathers alone. The drawback of such blends is reduced durability of the equipment. These feathers, especially those cut during processing, have sharp ends that can often pierce and damage the delicate down-proof fabric.

It is very rare to achieve 100% pure down. This is only possible through manual separation of feathers from down. For example, in Iceland, down is collected from wild geese and is hand-gathered from their nests. This variety is the highest-quality and most expensive down in the world.

4. Origin

Here, one can encounter many myths. Generally, the country of origin does not affect the quality of the down. Siberian geese do not have warmer feathers than Spanish geese. However, there are places where we can be confident about the quality of the down due to laboratory facilities and certification. An example is the Kołudzka goose, a breed developed by the Experimental Department of the Institute of Animal Science, which is valued worldwide. Certified down also ensures ethical sourcing and provides specific standards, such as the ratio of down to feathers or its loft.

5. Down weight 700 CUIN, and thermal comfort:

What to consider when choosing insulation?

Artificial insulation used in clothing, known as wadding, batting, or high-loft fiberfill, is a blend of polyester fibers pressed into a single continuous sheet. It is moisture-resistant, which is its main advantage over down (well, aside from the price).

If you have already decided on this type of insulation, what should you consider when buying it? The composition is always 100% polyester, so the main factors that determine the insulation performance are its weight and thickness.

Insulation weight and thermal comfort

Influence of insulation mass on thermal comfort?

Wadding can be applied in layers to achieve a higher level of insulation, or the appropriate thickness can be purchased directly. Below is a table to help you select the suitable weight of wadding for your needs. However, keep in mind that thermal comfort is highly individual, so consider this as a starting point for your own experiments.