Sleeping bags
When your days are filled with elevation gain and your nights with dropping temperatures, your sleeping bag is not just a piece of gear - it’s your lifeline. The perfect down sleeping bag* for backpacking, thru-hiking, or mountaineering balances warmth, weight, packability, and durability for your specific adventure style.
You'll need to consider where you’re going, when, and how you’ll be traveling, as well as to understand the materials, temperature ratings, and practical features. All of that will ensure a safe and comfortable sleep - no matter where the trail takes you.
* Synthetic sleeping bags are not covered here, as they are inferior to down in every parameter, except for the price, and the one thing you shouldn't skimp on is your sleeping bag.
| Use | Recommended Features |
|---|---|
| Thru-Hiking / Ultralight Backpacking | 850–950 fill down, 600–900 g weight, comfort rating around 0°C to +5°C |
| 3-Season Mountain Backpacking | 700–850 fill down, 1–1.3 kg weight, comfort rating -6°C to -1°C |
| Winter Mountaineering | 850+ fill down, 1.5–2.2 kg weight, comfort rating -20°C to -30°C, waterproof shell |
| High-Altitude Expeditions | Expedition-grade baffled construction, 900+ fill power, sub -30°C rating, full draft protection |
Why go down?
Down insulation, particularly high fill-power goose or duck down, is the premier choice for serious backpackers and alpinists due to its warmth-to-weight ratio and other advantages:
- Unmatched Loft: Traps heat efficiently.
- Lightweight: Ideal for long-distance or high-elevation trips.
- Highly Compressible: Saves valuable pack space.
- Long-Lasting: Retains loft over time with proper care.
Fill Power measures down’s loft - its ability to trap heat. The number ranges from 550 to 950+ and comes from a lab test that measures how many cubic inches of loft one ounce of that down fill produces. Fill power translated to use cases would be:
- 550-650: Standard quality budget or casual backpacking.
- 700-800: High quality serious 3-season and light alpine use.
- 850-950+: Premium quality ultralight and expedition use.
Modern sleeping bags often use treated (hydrophobic) down, which resists moisture and dries faster - crucial in damp or alpine environments.
Temperature Ratings
Sleeping bags use standardised ISO / EN ratings, which include:
- Comfort: Lowest temperature at which the average cold sleeper feels comfortable.
- Limit: Lowest temperature at which the average warm sleeper is still comfortable.
- Extreme: Survival-only rating, not recommended for general use.
Tip: Always choose a bag rated at least 5–10°C colder than the lowest expected nighttime temperature to provide a buffer.
Typical Use Cases
- 3-Season Backpacking / Thru-Hiking: Comfort rating around -6°C to 0°C.
- Alpine / High-Altitude Mountaineering: Comfort rating -18°C to -30°C or lower.
- Summer Fastpacking / Ultralight: Comfort rating around +5°C to +10°C.
Layering sleeping bags
By combining two sleeping bags (or quilts) - typically one for summer and one for 3-seasons - you can achieve warmth suitable for winter and alpine conditions without investing in a dedicated sub-zero sleep system.
For example, layering a 4°C (comfort rating) sleeping bag inside a -6°C one can provide a comfort level approximate to -23°C. This method is cost-effective and versatile, allowing user to adapt to various temperatures, and is very useful in alpine situations.
| Rating | 10°C | 4°C | -1°C | -6°C | -12°C | -18°C |
|---|---|---|---|---|---|---|
| 10°C | -1°C | -6°C | -12°C | -18°C | -23°C | -29°C |
| 4°C | -6°C | -12°C | -18°C | -23°C | -29°C | -34°C |
| -1°C | -12°C | -18°C | -23°C | -29°C | -34°C | -40°C |
| -6°C | -18°C | -23°C | -29°C | -34°C | -40°C | |
| -12°C | -23°C | -29°C | -34°C | -40°C | ||
| -18°C | -29°C | -34°C | -40°C |
Shape and Fit
Efficiency is everything: the shape of your sleeping bag dramatically affects both thermal efficiency and pack size.
- Mummy shape is most thermally efficient, as it reduces dead air space. Lightweight and packable.
- Slim/Expedition Mummy is even closer fit to maximise warmth and reduce bulk. Often includes draft collars, snug hoods, and trapezoidal footboxes.
- Women's-Specific Designs are tailored with narrower shoulders and extra insulation around hips and feet. Usually warmer for the same rating due to physiological differences.
Tip: A snug fit is warmer, but make sure you can move enough to sleep comfortably and wear extra layers inside if needed.
Shell Materials and Construction
Sleeping bag’s outer fabric is its first defense against the elements. Common shell fabrics are:
- 10D-20D Ripstop Nylon: Ultralight, used in high-end models.
- Pertex Quantum / Pertex Shield: High-performance shells with excellent wind and water resistance.
- DWR Coating: Adds water resistance without sacrificing breathability.
Baffles keep down evenly distributed. Box baffles are more efficient than sewn-through designs.
Draft Tubes/Collar seal warmth inside around zippers and neck.
Lining fabrics define comfort - soft-touch nylon or polyester taffeta is often used for skin comfort and moisture management.
Weight and Packability
When your bag is one of the heaviest single items in your pack, every gram matters. General weight ranges by use type are:
- Ultralight (Quilts or Minimalist Mummy Bags): < 800 g
- Standard Backpacking Bag: 800 g to 1.3 kg
- Winter/Expedition Bag: 1.3 kg to 2.2+ kg
Volume
Down bags compress extremely well. Look for a compressed volume under 10 litres for 3-season bags and under 18 litres for expedition-grade bags.
Tip: Use a compression sack or dry bag to reduce volume while keeping it protected from moisture.
Usability Features
Zipper Design
- Full-length: More versatile and allows ventilation.
- Half or ¾ length: Saves weight but sacrifices flexibility.
- Two-way zips: Enable foot ventilation.
- Tip: Some bags can zip together - ideal for couples.
Hood and Draft Collar
- A snug adjustable hood is essential in cold weather.
- Draft collars keep warm air around your neck and shoulders.
Footbox
- Anatomically shaped for natural toe splay.
- Some models offer extra insulation in the feet.
Practical and Ethical aspects
Sustainability & Ethics
- RDS-Certified Down: Ensures humane sourcing.
- Bluesign® Approved Fabrics: Indicates environmentally responsible manufacturing.
- PFC-Free DWR: Better for ecosystems and health.
Storage and Maintenance
- Air-dry after every trip.
- Wash only with special products and by following instructions.
- Use a large mesh sack, or hang freely for long-term storage.
