Down filled sleeping bags and clothing offer the highest warmth to weight ratio, highest levels of durability, and greatest compressibility of any type of insulation on the market today. Down has reached this level of performance by evolving naturally on birds. If you need the lightest and smallest sleeping bag available the answer is down, no question.
The finest down of all sits underneath the feathers of mature geese, and it is this that we are interested in. Although the highest quality goose down such as that used by Rab Carrington, Crux and Tundra stand alone in performance, even duck down bags are significantly lighter and smaller packing than synthetics of a similar warmth. So for high performance users the choice is fairly simple, and the selection of bags that we hold from Rabis filled with goose down in either 90% or 96% qualities or 85% duck down for those not wanting to spend megabucks. The Tundra bags are filled with goose down in 95% qualities. Those looking for a cheaper but still very warm option should look at the lower quality down used in the very warm Nanok White Goose Down bags.
What do all the rating figures mean?
This is the ratio of down to small feather in the filling and is expressed as a percentage. The higher the value the better (more refined) the down quality.
Duck or Goose and from where? Duck down tends to take the form of a central stem with fronds coming off it in a single plane (i.e. in a feather like pattern) whereas Goose down comes off a central stem in all directions to make a sphere of down or "cluster". This means that goose down can trap more air and therefore has a higher warmth to weight ratio than duck. Where the bird is from is also important. A goose that spends most of its time in Central Africa is going to have less effective down than one that spends most of its time within the Arctic circle. Goose age is also important - 3 year olds appear to be optimum as they have larger, stronger and more durable clusters.
What is this about? Tundra are a company who specialise in creating high performance bags from birds who have been kept compassionately. We are convinced that their down is the finest and by far the most ethical available. Down used in Tundra and now also Crux bags has been collected from geese in Poland. These birds have not been kept for use in the food industry. They moult every 4 months, and a proportion of the down found in the nests is collected to fill the bags. The birds live a natural life that is obviously excellent for their well-being, but also allows the down clusters to fully form, resulting in a high fill power and performance.
Aside from the ethical questions surrounding mass breeding of birds for food production and the less than ideal methods sometimes used, this means the down comes from mature birds. Poultry bred for food are usually killed young, long before their down has reached its full quality. Not only is the end product as ethical as possible, it is also of superb quality.
This is the ability of the down to loft (ie its ability to resist compression) and the higher the Fill Power value the better the quality of the down. To calculate the Fill Power a set weight of down is compressed by a specific weight and the volume it takes up under this condition measured. The actual measure is a minimum that must be attained by the down so the values have a + figure at the end. There are two measures of fill power to be aware of: European and US. We have stated European measures next to our down clothing and sleeping bags, but here are some comparisons to help you: 560+ European equates to 610+ US, 660+ European equates to 725+ US and 750+ European equates to 850+ US.
All of our down bags use forms of baffle construction. This means the down is housed in box compartments rather than tubes. The alternative, called stitch-through construction, leaves cold lines where the seams are, and is not at all suitable for high quality sleeping bags or down garments. The best baffles are not rectangular, but are slanted against each other or an arrangement of triangular prisms to prevent any cold spots. Crux provide an excellent explanation of the various construction systems on their webpage here.
Tundra Pure: -5, -10, -20 These three bags are filled with 400g, 600g and 800g of ethical Polish white goose down (as described above) to give comfort ratings of -5 through to -20 Centigrade respectively. The bags also have some excellent design features to achieve the best possible warmth. Firstly, the zipper is on the top edge of the bag so that less chill is picked up from the ground. The neck collar is higher at the back to fit the shape of the neck better than most, and finally there is extra down in the foot area to keep the feet 5 degrees C warmer- useful because a lot of heat is usually lost through the feet. There is a waterproof coating on the foot area and part of the hood so that droplets of water will sit on the surface rather than pass easily into the down, thus maintaining the loft in those areas where the sleeping bag might get damp from contact with a tent shell or bivi bag.
Tundra Pure and Dry: -5, -10, -20 These bags are the same except that the waterproof coating covers all the outer shell, though the seams are not taped. This gives greater protection from droplets of water, hoar frost melt and from your tea! Great for use above the snow line where spindrift blowing into the tent could occur, or in snow holes.
These bags are generous in size, so great for people with broader shoulders. Tundra do offer smaller sized bags for ladies- contact us for more info and delivery times.
Torpedo: 500, 700, 900 Crux have developed a lightweight, waterproof and breathable range of sleeping bags that use an amazing EU 860+ fill power Polish white goose down housed in vertically (chest area) and horizontally (legs) aligned V-baffles. The 20 Denier nylon baffles are welded directly to the eVent waterproof shell to keep weight low and the bag as durably down and waterproof as possible. The 3-4 length zip uses scuba dive suit technology to keep the bag waterproof along its opening, and is insulated with double draught tubes. The Torpedoes are without doubt the finest fully waterproof, fully breathable sleeping bags available.
They also come in 3 sizes. Not only does a smaller bag reduce the amount of weight a woman or smaller man has to carry, it reduces the amount of extra space inside the sleeping bag. Too much space takes energy to warm, and will result in a less efficient sleep, so getting the right size really does make a difference.
Rab Atlas : 500, 750, 1000 These use a very simple straight box wall construction, and are filled with 85% European Duck down with a 560+ EU fill power encapsulated in a Pertex® 4 shell. They are designed for general camping, backpacking and travel needs but where performance is key, but weight isn't paramount.
Rab Summit: 300, 300 1-2 zip, 700, 900 The 96%, 750+ EU fill power goose down on the top of the bag and 90%, 660+ EU goose fill on the base makes for a great combination of weight to warmth whilst the Endurance coated ripstop nylon of the outer shell and hood is highly breathable and yet water repellent. Trapezoidal baffles eliminate cold spots and down migration. If you need to be able to bivi out in sub-zero conditions with just a sleeping bag then one of these may be for you. Of course if you have a bivi-bag already, then this will be unnecessary, but for many people the extra 700-800 grams this weighs will be too much. Our feedback so far has been that for sleeping in the snow in Scotland the shell is totally adequate (good for when the argument inside the bothy starts to get too enthusiastic). Condensation dripping off the inside of a tent won't penetrate it, but biviing in wet snow may be different. Not as waterproof as the eVent-shelled Crux Torpedo series.
Rab Quantum-Q series: 250, 400, 600, 400 Endurance, 600 Endurance Adventure racers, ultralight Alpinists or anyone who needs to keep weight and bulk to an absolute minimum should look no further than this range. They all use the very best down available 96% white goose with a 750+ EU fill power and fulfill a variety of needs. The 250, 400 and 600 all use Pertex Quantum fabric, which at 30g-m2 is the lightest available, for their inner and outer shells. They also use a box wall construction which means a minimum use of fabric to retain the down in place. Iit does mean that you don't get the luxurious comfort that more complex baffle offers), but they are the lightest available. The 400 and 600 Endurance models use the same fill and construction as the standard options but use Pertex Quantum Endurance as their outer shells, which weighs 50g-m2. So whilst they are heavier (about 80g per bag) they are more durable, have greater water-resistance and are windproof.
The Quantum Topbag takes the theory of differential fill to the extreme. Differential fill takes into account the fact that the down underneath you doesn't trap air to keep you warm as it is too compressed by your body weight. Differential fill is used in the Summit range too, to a lesser degree. In this case there is no fill at all on the bottom of the bag, hence the name Topbag. The advantage therefore is that Topbags retain an amount of warmth as a traditional sleeping bag would with the same upper surface fill, but they are much lighter and pack much smaller as there is no base layer of fill. What this does mean though is that the bag must be used in combination with a mat to keep you protected from the strong cooling effects of the underlying ground surface, so there is extra weight here, but most people would use a mat anyway. The other key is that you need to be the sort of person that sleeps soundly in one position. You don't want to spin the bag around and end with the fill beneath you! Most people place their thermarest inside tha bag to help stop this, but that takes up room and means that you need to sleep on your back. So all in all you can save laods of weight and bulk but you won't get as luxurious a sleep as in a standard bag!
To get more of an idea of the advantages of these bags and other lightweight kit give Ben's discussion on the state of lightweight expediton gear a scan.
Rab Expedition: 900, 1100 If you are looking for warmth and comfort at extreme altitudes and in polar regions you can't go past a Rab Expedition bag. Click here to reach our Extreme Expedition Down Bag section.
Nanok Performance WGD -20 This bag is filled with 980g of goose down to give comfort ratings of -20 degrees Centigrade. The bags have some excellent design features at a great price. The zipper is on the top edge of the bag so that less chill is picked up from the ground and the neck collar is higher at the back to fit the shape of the neck better. They are heavy than the top of the line bags, but will still keep you warm in very cold conditions.
A super lightweight 3 season down bag Weight: 760g Fill Weight: 450g Pack Size: 8.9 litres (35 x 18 cm Ø) Comfort limit: 0°C Lower limit: -5°C
The perfect year-round sleeping bag for the mountain enthusiast, tailored towards multi-day trekkers and spring/summer mountaineersRab Fluorocarbon free Hydrophobic Down developed in conjunction with Nikwax Insulation - 650FP R.D.S. Certified European Duck Down:,400g 965g Mummy taper shape Pertex Quantum Pro outer fabric Trapezoidal chamber design to eliminate cold spots ¾ length YKK® 5 coil main zip with full length baffle Internal stash pocket Internal 3D collar and hood drawcord Lightweight Nylon Ripstop inner fabric 650FP R.D.S Certified European Duck Down Left zip only Temperature tested to new European standard: EN1357:2016 Cotton storage sack Dry bag compression stuff sack Angled foot box Limit -6°C (21°F)
The perfect year-round sleeping bag for the mountain enthusiast, balancing weight, comfort and warmth into one bag.Rab Fluorocarbon free Hydrophobic Down developed in conjunction with Nikwax Insulation - 650FP R.D.S. Certified European Duck Down:,600g 1173g Mummy taper shape Pertex Quantum Pro outer fabric Trapezoidal chamber design to eliminate cold spots ¾ length YKK® 5 coil main zip with full length baffle Internal stash pocket Internal 3D collar and hood drawcord Lightweight Nylon Ripstop inner fabric 650FP R.D.S Certified European Duck Down Left zip only Temperature tested to new European standard: EN1357:2016 Cotton storage sack Dry bag compression stuff sack Angled foot box Limit -10°C (14°F)