We have tested selected sleeping bags for you. In the snow cave after the ski tour, on the river bank during the lockdown and in the exposed bivouac on the wall foot. You can find out how we rate the sleeping bag models from Mammut, Sea to Summit, Mountain Equipment and Grüezi Bag here.

Laboratory tests are all well and good. But what really matters are the real experiences during a night outdoors, in a bivouac sack or in a tent. In the past months we have put the following models through their paces for you.

  • Mammut Women's Protect Down Bag
  • Sea to Summit Spark 3
  • Mountain Equipment Earthrise 600 Women's
  • Grüezi Bag Hybrid Ice Extreme

Poodle comfort in the snow cave

We have always dreamed of a sleeping bag in which you don't freeze despite the sub-zero temperatures, even though you only wear a T-shirt and underwear to sleep. With a little skepticism, we set off shortly before the outbreak of the Corona crisis. Off into the air, into the elaborately buried snow cave. The Women's Protect Down Bag from Mammut and Hybrid Ice Extreme from Grüezi Bag were also part of the party.

After a fine cheese fondue in a down jacket and trousers, we went out of our clothes and into our sleeping bags. We asked ourselves the question: "Are we going to shiver like the castle dogs for a night or enjoy our morning coffee rested?"

Practical detail: Thanks to the zippers on the side of the Mammut Protect Down Bag, morning coffee can be prepared and drunk while warm.

Comfort despite minus temperatures

We only had the answer to this question at sunrise. We both slept perfectly. So the sleeping bags kept their promise: comfort despite sub-zero temperatures. How well the sleeping bags are insulated could also be seen from a small detail: snow that fell on the sleeping bag did not melt overnight due to the body heat.

Offers protection and warmth despite snow flurries: The Grüezi Bag Hybrid Ice Extreme.

What we particularly liked about the Mammut Women's Protect Down was the soft fabric insert in the head area. This prevents the usual crackling when moving and is more pleasant than the cover material used in sleeping bags. What we especially liked are the side openings for the arms. Thanks to this detail, breakfast and coffee can be prepared without having to crawl out of the warm sleeping bag.

The sheep's wool in the Hybrid Ice Extreme by Grüezi Bag protects the down from moisture.

Of course, we liked an optional gadget on the Hybrid Ice Extreme: a heating element in the foot area that can be operated using a power bank. If you do not need such a luxury or simply want to save weight, you can remove the heating element quickly and easily.

Another special feature of the Grüezi Bag model is the use of sheep's wool as an additional insulation layer. Wool can absorb 30% of its own weight in moisture and thus protects down, which only insulates well when it is dry.

Mammut Women's Protect Down Bag

  • Comfort range (manufacturer information): minus 13
  • Weight: 1810g
  • Soft fabric in the head area (pleasant, no rustling)
  • Puffs up incredibly strong
  • Good space
  • Main zipper in the middle
  • Thanks to the side openings, you can stretch your arms out of the sleeping bag and operate the stove.
  • Price: 650 CHF

Grüezi Bag Hybrid Ice Extreme

  • Comfort range (manufacturer information): minus 8
  • Weight: 1450g
  • Intelligent combination of wool and down feathers
  • Anti-hacking zipper
  • Anti-slip material on the bottom
  • Heating element in the foot area
  • 694 CHF

Both sleeping bags are very warm models. So they are primarily suitable for really cold nights with temperatures in the minus range. Even if the zippers can be opened, the sleeping bags are very insulated as a "blanket" and you sweat underneath when the outside temperature is too high.

Adventures around the corner during the Corona crisis

The corona-related restrictions in Switzerland were relatively small - but still existed. Instead of an adventure in the distance, we saddled our bikes and drove to the river two kilometers away. A starry night with temperatures around 3 degrees awaited us.

Waited patiently for his use: The Mountain Equipment Earthrise 600 Women's sleeping bag

The Earthrise 600 model from Mountain Equipment specifies a comfort range of -1 degrees Celsius. Our overnight stay on the river was around 3 degrees cold and the air was quite humid. We spent the night in the open air directly on the shore. Due to the humidity, the sleeping bag got a little damp during the night, but still kept us warm enough.

The down filling and outer material of the Earthrise 600 from Mountain Equipment are 100% recycled!

With its small pack size and weight (1030g), the Earthrise 600 is ideal for multi-day tours or excursions where you still have to carry rope, express slings and other materials. What is special about the Earthrise: The outer material and the down filling are made of 100% recycled material. The down is extracted from old products and processed for a second life.

Mountain Equipment Earthrise 600 Women's

  • Comfort range (manufacturer information): minus 1
  • Weight: 1030g
  • Outer material and even down feathers are recycled
  • The waterproof stuff sack protects the sleeping bag from moisture during transport
  • Elastic seams bring the sleeping bag closer to the body and thus reduce unnecessary "air" in the sleeping bag that has to be warmed up by the body
  • Price: 394 CHF

Bivouac night on the wall foot with the lightest sleeping bag in the test series

Another sleeping bag model accompanied us on an alpine adventure in mid-May. Since it was about setting up a new climbing route and we had to carry an incredible amount of material up, we decided on the lightest model: Spark III from Sea to Summit.

The Spark III from Sea to Summit is super light and still has a comfort range of minus 2 degrees.

The sleeping bag weighs just 665g and can be compressed extremely small. Nevertheless, the Spark III offers a comfort range of minus 2 degrees Celsius and is therefore an ideal sleeping bag for alpine tours with an overnight stay in a bivouac.

Our companion in the bivouac had the Spark II model with a comfort range of 4 degrees Celcius. After the night, with temperatures around four degrees, it has been shown that the 3-series model has proven itself better. We should agree that the comfort information of all manufacturers should be used with caution. Although we are not one of the most sensitive to cold, we believe that if you really want to sleep without freezing, the comfort range given should be slightly above the effective temperature.

Important note: We slept with a T-shirt and long underwear.

Sea to Summit Spark III

  • Comfort range (manufacturer information): minus 2
  • Weight: ultra light 665g
  • Small pack size
  • Puffs up a lot
  • Impregnation protects the down from moisture
  • 559 CHF


If you are looking for a sleeping bag for the winter months or for high alpine tours, you are with the models Hybrid Ice Extreme from Grüezi Bag or that Protect down bag very well served by Mammut. Those who are more likely to be traveling in higher regions in spring and autumn, perhaps once in the summer months, will go to Spark III from Sea to Summit and that Earth rise 600 have his pleasure.

We liked the Protect Down Bag from Mammut best for the very warm sleeping bags. He kept us so warm, we had the feeling that it was impossible to freeze in this sleeping bag.

In the second group, we are absolutely thrilled with the Spark III. We never thought that a sleeping bag with such a small pack size and weight could achieve such good thermal performance.

We used these sleeping mats

The quality of the underlay should not be underestimated. Without a good sleeping mat, a lot of cold penetrates from the floor to the sleeping bag / body and cools down a lot. We used the sleeping mats as a base for the tests EtherLight Insulated & Comfort Plus SI Women from Sea to Summit as well as the model Aerostat Synthetic 7.0 accompanied by mountain equipment.

EtherLight Insulated from Sea to Summit

With a weight of 490g, this sleeping mat (regular size) is one of the lightest on the market, but still achieves an R-value of 3.2. Stowed in the pack sack, the mat hardly needs any space in your backpack.

Ether Light XT Insulated Sleeping Mat

Comfort Plus SI from Sea to Summit Women's

The second mat that accompanied our female tester was the Comfort Plus SI. The name says it all. The mat is more comfortable than the EtherLight Insulated and has an R-value of 4.1. At 970g, it is also significantly heavier.

Sea-To-Summit_Comfort-Plus-SI_Sleeping Mat Women

Aerostat Synthetic 7.0 from Mountain Equipment

The sleeping mat Aerostat Synthetic 7.0 also accompanied us. In terms of weight and packing size, the model is in the middle range (665g) and has an R-value of 4.0.

Tips for handling your sleeping bag

We would like to give you a few tips that are important when dealing with a down sleeping bag. You can find more information on sleeping / sleeping bags in the following articles.

  • Do not keep your down sleeping bag in the compression bag at home. The above models come with an extra bag in which you can store the sleeping bag without compression. Important: store dry.
  • Take your sleeping bag out of the compression bag 15-30 minutes before going to bed so that the down feathers can puff up optimally.
  • Often dew forms at night, which makes your sleeping bag damp. Even if your sleeping bag is impregnated - the less moisture, the better. If you can, put a tarp over you or sleep under a tree or ledge.

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Credits: Images provided