Best Sleeping Bags UK (2026)

Down, like the Mountain Equipment Xenith III or Exped Ultra 0° here, gives the best warmth-to-weight ratio and packs smaller, but loses much of its insulating power when wet unless treated with a hydrophobic coating. Synthetic fill, like the Nemo Soul or Marmot Trestles Elite Eco here, is heavier and bulkier but keeps insulating even when damp, which suits genuinely wet UK conditions.

The comfort rating is the lowest temperature at which an average person should sleep comfortably, while the limit rating is the lowest temperature at which they can sleep without waking from cold, though not necessarily comfortably. It's generally safer to buy for the comfort rating of the coldest conditions you expect, not the limit rating.

Fill power measures how much a given weight of down expands to trap air, so a higher number (like the Exped's 850 or Mountain Equipment's 900) means more warmth for less weight and bulk. Lower fill power bags, like the OEX's 600, can still perform well but need more down by weight to achieve the same warmth.

For backpacking where every gram in your pack matters, an ultralight bag like the Big Agnes or Exped here is a genuine, worthwhile investment. For car camping or shorter trips where you're not carrying the bag far, a heavier but cheaper option, like the Deuter Orbit here, gives most of the comfort without the premium price.