Synthetic sleeping bags

Down is not your only choice: synthetic sleeping bags

If you don’t want to carry a bivvy bag with you or you'll travel in areas with rapidly changing weather conditions, then it's better to opt for a synthetic rather than a down sleeping bag. Keep on reading to learn more about what to consider when buying a synthetic sleeping bag.

What kind of fill is found in a synthetic sleeping bag?

Synthetic fibre can be thought of as a giant wad of cotton. The lining is made up of tiny micro-threads that twist thousands of times to insulate warm air in the spaces between them. If the fibres themselves also trap air to improve heat retention, then these are called hollow fibres.
Synthetic fibres attempt to imitate down, which has certain advantages and disadvantages compared to the natural fibres. A synthetic sleeping bag can keep you toasty even if it gets wet, and it won't clump together. Synthetic fibres can’t loose any fill because they form a continuous filament. However they’re nowhere near as warm as down (when comparing two sleeping bags that weigh the same) and they're less vapour permeable.
Another thing to keep in mind is the price: if you want a sleeping bag for all occasions and you’re not concerned about weight or pack size, then get a synthetic one!

Where and when to use synthetic sleeping bags

Synthetic sleeping bags are mainly used in changeable weather conditions, e.g., in humid tropical climates or in cold, damp weather. You can also use them if you’d like to spend the night outdoors without a bivvy bag. In addition, even if the synthetic sleeping bag gets wet, it’ll still keep you toasty warm. Down tends to clump together when wet and therefore loses its ability to insulate.

The construction, types and features of synthetic sleeping bags

There are synthetic sleeping bags that come as a blanket and some as a mummy style. The former provides more comfort, while the latter provides more heat retention. In addition to connectable models, there are also women-specific sleeping bags on the market that feature a soft lining and have more insulation at the feet. Some other features to look out for are a draught collar, which is super practical in cooler temperatures and a two-way zip that provides more ventilation. Synthetic sleeping bags with L-shaped or U-shaped zips are even more versatile.
Of course, having only a synthetic sleeping bag doesn't guarantee a comfortable night's sleep. You'll also need to find a good sleeping mat. This combination will help you recharge your batteries for the next day of adventuring.