sleeping bags usually have a classification dependent upon the season with Spring, Summer, Autumn and Winter but there is also an additional classification of Expedition. There is no industry standard and as a result interpretation of these classifications can and does vary between manufacturers.
The classification does however come with a temperature guide as well and the table below shows the minimum temperatures the sleeping bags are designed to be use at.
The classifications do not and can not however cover all situations as we all know that the vagaries of the weather across Europe can at times lead to extremes.
Quilted or Stitched Through single layer construction holds the sleeping bag filling in baffles or channels but results in cold lines along the stitching. This type of construction is not suitable for sleeping bags used in cold weather.
The next step up is a double quilted or stitched layer where the stitching is offset to reduce the problem of cold lines.
The majority of synthetic fill sleeping bags use hollow threads trapping more air to warm up and reducing the overall weight of the bag.
Natural Goose Down
Goose Down naturally insulates geese and sleeping bags. Goose Down is preferred to Duck Down because the feathers have softer spines that could pierce you or your page.