Types of Sleeping Bags on the Market

The types of sleeping bags available on the market are more or less similar. Currently, commercially sold sleeping bags are classified by material into down sleeping bags and cotton sleeping bags; fleece sleeping bags will not be discussed here.

Down Sleeping Bags

Down materials can be further divided into white goose down, white duck down, grey duck down, waterfowl down, and so on. Down provides the most effective warmth retention per unit weight. Down sleeping bags are relatively warm, easy to compress, capable of retaining their original shape well, and have a long service life. However, they have some disadvantages: they are relatively expensive, tend to absorb water, and a wet down sleeping bag offers extremely poor warmth retention. Moreover, it takes more than a full day to dry completely, usually only when exposed to sunlight.

Down mainly has three key performance indicators:

The first indicator is fill weight. For example, a "400g goose down sleeping bag" or a "1100g duck down sleeping bag" — this weight does not refer to the total weight of the sleeping bag, but rather the net weight of the down used for filling.

The second indicator is down content. Down consists of feather pieces and fine down clusters. Feather pieces play a supporting role, while warmth retention mainly comes from the fine down clusters. Down content is expressed as a percentage; for instance, "80% down" means that 80 weight units out of 100 are fine down clusters. The maximum down content of duck down is generally between 85% and 90%, while that of goose down can reach 90% to 95%.

The third indicator is the fill power of the down. Fill power (referred to as "Fillpower") is defined as the volume (in cubic inches) that one ounce of down occupies under a pressure of 68.4 grams. The higher the fill power of the down, the better its warmth retention performance. Generally, the fill power of domestic duck down is around 450, while that of domestic goose down ranges from 450 to 600.

Sometimes, extremely cheap down products can be found on the market, such as down jackets priced at 100 yuan each or duck down sleeping bags at 150 yuan each. Such products are generally not recommended for purchase. This is because down has two additional indicators that ordinary people cannot inspect on-site: oxygen consumption index and cleanliness. Down needs to go through multiple professional cleaning and degreasing processes. Some small vendors simply give primary down a basic cleaning before turning it into finished products, and these products are essentially unusable. A simple way to identify such substandard products is to tap the finished product with a wooden stick — if dust leaks out, or if there is an unpleasant odor when you smell it, or if the water emits a foul smell when the product is washed, it is a poor-quality item. Down itself is a high-quality material, so it is hoped that everyone will choose truly good-quality products.

Fiber Cotton Sleeping Bags

Fiber cotton has relatively good moisture resistance, and even a wet fiber cotton sleeping bag can still maintain a certain level of warmth retention. It dries quickly and is low in price. However, it is slightly heavier than a down sleeping bag of the same grade, difficult to compress, takes up more space when packed in a backpack, and has a relatively shorter service life.

There are many types of fiber cotton, with varying quality — ranging from ordinary glued cotton to four-hole cotton, seven-hole cotton, 3M cotton, POLARGUARD 3D/HV cotton, and more. The filling density is expressed in grams per square meter, such as 250g/m² or 300g/m².

When comparing the two types of fillings — down and fiber cotton — down offers higher warmth retention, and can achieve the lightest weight under the same level of warmth retention; fiber cotton has relatively lower warmth retention and a larger packaging volume; down is expensive, while fiber cotton is very affordable; fiber cotton sleeping bags can be directly machine-washed, while down sleeping bags are more troublesome to clean; down loses almost all of its warmth retention ability when wet and is not easy to dry; fiber cotton has a certain water-repellent property, can maintain a certain level of warmth retention when wet, and dries quickly.

Unless you are heading to an extremely cold and harsh environment, generally speaking, buying a medium-hole fiber cotton sleeping bag is sufficient for winter use. Such sleeping bags have a comfort temperature rating above -5°C, with a relatively suitable volume and weight — and most importantly, they are affordable.