Sleeping Bags

Temperature interpretation

Perception of warmth

The perception of temperature of human beings is very individual und subjective. It depends of many factors such as:

  • Sex (Females generally feel colder than Males)
  • State of exhaustion (an exhausted body feels cold fast)
  • Hunger (a hungry body feels cold faster than a well fed)
  • Experience (How used a person is to sleeping in a sleeping bag)
  • Influence of Alcohol

There are also objective measurable factors that have an impact on temperature perception while sleeping:

  • Wind-chill (always try to protect from wind!)
  • Insulation from the ground (on the ground the insulation gets compressed and looses its power. -> Whenever possible use a sleeping mat)
  • Humidity (wet climates feel colder)

Evaluation of temperature settings

Since 2002, a definition for temperature ratings on sleeping bags exists with the European Norm 13537. Temperatures are rated with the help of standardised climate chamber tests.

Ajungilak cooperates with the Swiss EMPA and the Spanish Aitex institutes, to work out temperatures in accordance with the EN Standards.

Tmax - Tcomf - Tlim - Text
The range between Tmax and Tcomf is described as the comfort range. Between Tcomf and Tlim is the transition range, below this and down to Text is the risk range. Tcomf can also be understood as the comfort limit for a woman and Tlim as that for a man. Above these temperatures, the average woman or man can sleep without stress or shivering. The extreme temperature Text can only be tolerated for a limited time of 6 hours. However, the bottom line is that these are just laboratory values. Temperature information should not therefore be understood as guaranteed values. It is intended purely for reference and to allow a relative comparison of different sleeping bag models.

Strong feelings of coldness should be expected in the risk range (blue). There is a risk of damage to health as a result of hypothermia.

Practical tips

If you are planning a trip to the wilderness or high mountains, make sure that you have sufficient ability, knowledge and adequate equipment to deal with all possible surprises the weather may have in store for you. Make sure that you know where the next refuge is located and how far it is from you.

Sleeping bag. Contrary to widespread belief that warmer is better, a sleeping bag can actually be too warm. Excessive sweating leads to wet clothing and wet sleeping-bag filling (particularly in the case of down). This makes you feel cold, despite the fact that you are expecting a warm sleeping bag.

Iso mats. A good insulating iso mat is just as important as a good sleeping bag. For winter tours, we recommend self-inflating mats of at least 3.8 cm thick.

The weather. Over a five-day period, the weather usually changes by plus/minus 5°C, and in stormy conditions the changes can be far greater. You also get wet, tired and cold if it rains or snows. Lying in your sleeping bag after hiking in the pouring rain reduces cold protection, since the sleeping bag is damp and you are tired. Check out the long-range weather forecast.

Altitude. The night temperature in the valley may be warm, but high in the mountains it is far colder. As a general rule of thumb, expect the temperature to fall by 5°C for every 1000 metres of altitude. The weather in the mountains can also be far more extreme than in the valley.

Even the best sleeping bag cannot replace the following safety precautions:

Take extra clothing with you. Even in summer, we recommend that you carry expedition undergarments with you, in particular a thermal vest with long sleeves and long leggings. A full set weighs just 400 grams and can be used day and night. You can wear it under your normal clothes during the day, and on cold nights you can sleep in it as well. Where possible, wear clothing that effectively transports moisture away from the body (no cotton). Each night, a sleeper loses 3 to 5 decilitres of water in the form of sweat. If this moisture is not transported away from the body, you can soon start to feel cold. If you are expecting sub-zero conditions, take a face mask and bivouac socks with you too. The heat of the sleeping bag can easily be increased: by wearing expedition undergarments, a storm cap and socks.

Make sure you eat enough. If you do not eat enough, your body will produce less heat and you will feel colder. When you are hiking you need a lot of energy to carry you forward. Make sure you drink enough fluids - but avoid alcohol: dehydration reduces the body's ability to produce heat. Liquid intake is therefore very important. Drinking tea or hot chocolate in the evening is better for you than alcohol. Alcohol makes you feel warmer to begin with, but when it wears off you feel the cold even more.

Keep your things dry! Wet clothing and sleeping bags (especially with down) provide far less insulation against the cold than dry items. Try to keep spare clothes and sleeping bags dry. Keep them in a waterproof backpack or plastic bag in your rucksack. Try to keep rain, snow and mud out of the tent. If possible, try to place your sleeping bag away from the tent walls. Open the ventilation flaps in the tent to avoid condensation. Wherever possible, dry the sleeping bag in the open air - for example on the tent.

Wear extra clothing! If you have brought this with you, then you will need it. If you are cold, increase the heat of your sleeping bag by wearing expedition undergarments, a cap, a face mask and socks.Use a sleeping bag insert. This will improve the heat capacity by around 5°C and protect the sleeping bag from dirt.

Unpack your sleeping bag at once! Remove your sleeping bag from your backpack as soon as you have put up your tent. Shake it to allow the filling to puff out. Exception: if you are wet through, wait until you have changed. Move around to warm up before going to sleep. This boosts the circulation and makes the body generate heat.

Tips when it is getting cold during the night

  • Wear additional clothing in the sleeping bag (e.g. socks, expedition underwear and hat).
  • Make sure you protect against cold from the ground (best use an insulation mat or if not available use straw, wood, foam or cardboard).
  • Make sure you have eaten enough calories before going to sleep.

Sleeping bag care

  • Don't leave the bag in the compression sack for long periods. Store it loosely or put down bags in the provided store bag and synthetic bags with loosen compression straps.
  • Air the bag after use. Remember the human body gives off about 1/3 of a litre of perspiration each night.A sleeping bag liner and/or an outer bag extends the life of the bag, as well as increasing the warmth effect.
  • Do not roll your bag. Starting with the foot end, stuff the bag into the stuff sack, take care to distribute the bulk evenly. Rotate the bag as you stuff and kneel on it if necesssary. This will extend the lifetime and performance of the filling.
  • Wash your bag only if really necessary. E.g. if it is very dirty, stinks or the Loft is shrinking.Ajungilak sleeping bags are are mothproof and non-allergenic.

How to wash a down or synthetic-fiber sleeping bag

Adjust the water temperature according to the care instructions

Wash in a washing machine (note information above!) on double rinse cycle or by hand in the bathtub. To hand wash, till the tub with water and add special detergent. Submerge the sleeping bag in the suds with the zipper closed, let it soak for about 1 hour and then rinse thoroughly several times. Press the water out gently (under no circumstances wring the sleeping bag out) and carefully lift it out of the tub.

How to dry a down sleeping bag

Spread the sleeping bag out to dry at room-temperature on a large washing stand. The down clumps that are stuck together in the chambers must be pressed out every 30 minutes. After 4 hours loosen up the clumps by hitting the sleeping bag with your hand. After two days shake the sleeping bag out and it will be almost dry. You can now complete the drying process in a large tumble dryer (at least 10 kg capacity). Look out for hot spots in the tumble dryer, as these can burn the outer fabric! If you use a tumble dryer (at least 10 kg capacity), please be sure to set it to no more than 40°C. Close the zipper and add a few tennis balls to loosen up the filling.

How to dry a synthetic-fiber sleeping bag

If you use a tumble dryer, please be sure to set it to no more than 40°C. Look out for hot spots in the tumble dryer, as these can burn the outer fabric! Close the zipper and add a few tennis balls to loosen up the filling.

Drying time without a tumble dryer: approx. 24 hours.

Down loss

To offer a comfortable temperature, sleeping bags must be air-permeable. However, this has the consequence that the finest strands of down can work their way through the fabric. It is important to understand that down loss does not mean that the fabric is damaged or inferior. The best solution is to pull the stray down back into the filling from behind . The small hole where the fibers have separated will usually repair itself through natural repositioning of the fibers as the sleeping bag is used. This process can be accelerated by gently rubbing or massaging the fabric in the area around the hole.

Do not pull the down out of the sleeping bag! Inside the sleeping bag the down clusters are mixed together and sometimes linked together. If you pull out one down cluster, another will follow. This will unnecessarily increase the hole between the fibers.There are no breathable down sleeping bags that have absolutely no down loss. The loss of a few strands of down lies in the nature of the technology and does not mean that the product is faulty. Losing a few down strands will not reduce the insulation of the sleeping bag. Our cooperation with the world's leading fabric suppliers, who provide guaranteed ultra-dense-weave down quality, means that we are able to guarantee absolute top performance.