Blog - Camping Information

Which sleeping bag insulation is right for you?

With a lower temperature than your body, a sleeping bag on its own is naturally cold. It’s only once you get in it that it is warmed up, taking heat from your body. The purpose of insulation is to trap as much of this heat as possible - without it, much of the warmth your body generates would be lost, and you’d be in for a tough night’s sleep.

Insulation is one of the most important elements of a sleeping bag then, and insulation materials therefore one of the key factors to look for. Sleeping bag insulation materials generally boil down to two types: natural and synthetic.

Natural insulation

Down insulation

Down is the main and perhaps best natural insulator for sleeping bags, though it does come at a premium. Found underneath the tougher external feathers on birds such as Ducks and Geese, it is lightweight, compressible and traps heat incredibly well.

The quality of down is measured by ‘fill power’, which measures how many cubic inches one ounce of down will fill. The higher the fill power the larger the down cluster, which means it will trap more air and warmth, be more comfortable and last for longer.

A fill power of around 550 is used for mid-range sleeping bags, whilst 650 or more is considered the best.

It’s also important to consider what percentage of a sleeping bag is made up of down – a good bag will be 85%, whilst the best often claim to be more than 95%.

Pros	Cons
Can be compacted to a much smaller size than most other forms of insulation	More expensive than other forms of insulation
Weighs very little	Loses most of its insulating abilities when wet
Insulating abilities are incredibly difficult to recreate, meaning it is unmatched by synthetic materials
Very good warmth to weight ratio

Synthetic insulation

Made from poly fibres, synthetic insulation is used in all ranges of sleeping bags. Whilst synthetic materials can be good insulators, they do not completely replicate the qualities of down.

Pros	Cons
As it is manmade, synthetic insulation is much cheaper than down	Less effective at retaining heat when compared to down
Maintains a lot more of its insulating abilities when wet	Because of its weaker insulating properties, more is needed to maintain similar temperatures to that of down, making it much bulkier and heavier.
Much easier to care for

For family camping trips in the UK, where the weather is typically much wetter, a synthetic sleeping bag should suffice, as long as you pay careful attention to the comfort rating.

Those looking for more lightweight but still high performing sleeping bags should consider down, which often provides the same insulating abilities with half the weight.