Down Sleeping Bags Guide

Down-filled sleeping bags are superior to their synthetic filled counterparts in almost every way. They are warmer, lighter, compress smaller, retain their loft and insulating properties better and are more comfortable in a wide temperature range. If they are given a bit of care and attention they can last a lifetime. The initial outlay on a down-filled bag is always going to be higher than a synthetic filled equivalent, typically around 50% more, but taking everything into account, including the lifetime, then down-fill offers greater value for money.

The only real downside with down-filled sleeping bags is if they get wet. They take forever to dry and, until they do, loose almost all of their insulating properties unlike synthetic fill sleeping bags which will retain the ability to insulate even when quite wet.

Types of Down

Down is the term used to describe the soft, fluffy under-feathers of ducks and geese used by the birds themselves to provide retention of body heat. Goose down is considered to be the highest quality down available with Eider duck down next in line.

Most of the down used for filling sleeping bags is a by product of the food industry – it is only the highest quality goose down which is 'harvested' specifically. These birds are purpose bred and the down is gathered and sorted by hand during the bird's natural moulting cycle. As would perhaps be expected, the extra expense this entails is reflected in the end product's higher price tag.

Higher quality down filled sleeping bags will use pure down only, or a 95% down to 5% feather fill ratio, while lower quality items will bulk out the fill with coarser, larger feathers.

Fill Rating

This rating, which is used extensively with the top-end down products, describes how many cubic inches 1 ounce of down will displace. The best quality down has a high fill power meaning that less is needed in an equivalent space to achieve a certain temperature rating. This is because the best quality down is fluffier and lofts better making the finished product lighter and more easily compressible.

Anything under 500 fill power is considered mediocre quality, the 550 to 600 fill power marks denote good quality, 600 to 750 fill power are very good and anything which exceeds 750 fill power is considered excellent.


Sleeping bags comprise of an outer shell and an inner lining between which is sandwiched the filling. The three separate components then have to be held together and this is typically done with some kind of stitching. There are various different methods used which contribute something to the warmth efficiency of a sleeping bag and also its comfort.

All types of stitching create separate chambers of varying size and shape in which the down is held in place and these chambers are known as baffles.

The most basic form of construction is known as 'sew through' or 'stitch through' and is typically used on sleeping bags needed for warmer weather situations only as the method used makes the sleeping bag prone to cold spots.

There is a separate article on this site which explains the construction of both down-fill and synthetic fill sleeping bags in depth.

Care of Down-Filled Sleeping Bags

A good quality down-filled sleeping bag is an investment which needs a certain amount of care and attention to ensure it keeps all of its insulating properties and has a long life span.

Eventually all sleeping bags will need cleaning not least of all because body oils and dirt in themselves can affect a sleeping bag's insulating properties. However, going about this the wrong way with a down-filled bag can either significantly reduce the bag's ability to keep you warm or, in the worst cases, render it almost useless.

Dry cleaning is out but some sleeping bags can be machine washed where manufacturers guidelines allow it and ideally with products specifically designed for the purpose. Some down-filled bags will need hand washing which can be time consuming which is why some people opt to take their sleeping bag to an outdoor specialist who provides a cleaning service.

There is a separate article which details the washing procedures for both down-fill and synthetic fill sleeping bags.


Stuff sacks and compression bags are not designed for storing your sleeping bag long term – only for transporting them from A to B. Keeping your down-filled bag tightly compressed can affect its lofting abilities and  it can also damage internal baffles and seams – in both cases the thermal properties of your sleeping bag will be compromised.

Down-filled sleeping bags need to be loosely stored somewhere dry, and again, there is a specific article on this site which addresses the subject of storage in full.

Everything Else

When deciding which sleeping bag to purchase you will have choices which include shape, size, season rating, water repellancy, extra features and so forth. As these are common to both down-filled and synthetic filled sleeping bags they are not covered here. However, there are several separate articles elsewhere on the site which addresses each of these issues.