Sleeping Equipment

Everything between the ground and a night outside

Sleeping equipment is the whole system rather than a single item: bags filled with goose or duck down, hammocks for camp and garden, poncho style bags and the layers that go under and inside them. Judging a night outdoors by the bag alone is the usual mistake: warmth comes from trapped air, and that air is lost as easily to a cold floor or a draught at the shoulders as to an under filled bag.

Why does what goes under you matter as much as the bag?

Body weight crushes the filling directly beneath the sleeper, and crushed filling holds no air. That is why the underside of a bag insulates far less than the top, and why the ground draws heat away all night by simple contact. The answer is a barrier below rather than a warmer bag above, the job a sleeping mat does. Sleeping cold in a bag rated for the conditions usually points here rather than to a fault in the bag.

Down or synthetic filling in a sleeping bag?

Down clusters trap a lot of air for their weight and compress small, which suits walkers counting grams and volume. They lose loft when wet and dry slowly, so they want protection from condensation and rain. Synthetic filling is heavier and bulkier for the same warmth and copes better when damp, which suits car camping and wet climates. The filled bags in down sleeping bag sit at the light and compact end of that trade off.

What separates a warm night from a cold one?

• Shape: a tapered mummy cut leaves less air to heat, a rectangular cut is roomier to sleep in but colder for the same filling.
• Hood and neck baffle: warm air escapes at the shoulders first, and a drawn hood with a collar stops that draught more effectively than extra filling elsewhere.
• Zip baffle: an insulated strip behind the zip covers the one uninsulated line running the length of the bag.
• Packed size: check the compressed dimensions against the pack, since a bag that will not fit inside travels on the outside and gets wet.
• Length: feet pressed against the end flatten the filling, so a slightly long bag stays warmer than one that just fits.

Is a hammock a realistic alternative to a tent?

Where there are two solid anchor points, a hammock keeps the sleeper off wet ground and away from stones and roots. The trade off is underneath: with air on all sides, the compressed filling below the body loses heat faster than it would on the ground, so hammocks call for insulation below even on mild nights. In open country with no trees there is nowhere to hang one.

How should it all be stored?

Never compressed. Months in a stuff sack take the spring out of filling of any type, and lost loft does not come back. Keep bags loose in a large cotton sack or hung in a cupboard, and store them dry, since one put away damp smells of the last trip. A sleeping bag liner keeps skin oils off the filling and washes far more easily than the bag itself. That stretches the years between washes of a sleeping bag.