Since you are here and you are reading this text, this means you want to know what is mummy sleeping bag. So to give you a proper answer I shall start with a general description of sleeping bags shapes.
Roughly speaking we have the following three main groups with respect to shape:
- classic rectangular sleeping bags
- semi-rectangular bags
- mummy sleeping bags.
There are some more types with slightly different designs but they can usually be categorized as one of the three given above.
Sleeping bags have evolved dramatically regarding the fabric and weight. Those used by arctic explorers in the 19th century were of buffalo skin.
Rectangular Sleeping Bag
This is a classic design, good for many purposes. Here are a few:
- Usually, they have a zipper all along the two sides, and they can be unzipped so that you can use them like a blanket.
- You can also zip such a rectangular bag to another of the same type and make a bag for two people. In this case, it is necessary to buy them in pairs for such a purpose; one has the zip on the left side and another on the right side.
- There exist double-size rectangular bags for two people.
Perhaps a negative side of this type is that it is more heavy and bulky as compared with other types (see below) because more material is used, and longer zips. But they are more comfortable and provide more space.
On the other hand, more space means more surface and more possibility for losing warmth, so they are less thermo-efficient as compared with other shapes.
Mummy Sleeping Bag
They come in many sub-variants, just see this picture below to realize this:
Mummy bags are in principle lightweight, but of course, this depends on the fill. Essential features of a mummy bag are:
- Narrow in the foot area.
- They come with a hood.
- They are wider around the shoulder zone.
- As a result, they are less bulky as compared with rectangular bags.
- This is the most thermo-efficient shape.
- The zipper is usually one of these: full, 3/4, or 1/2. The reason for a shorter zip: to increase thermal efficiency and to reduce weight.
- There are mummy sleeping bags that can be zipped together.
- There exist double-size mummy sleeping bags, for two people. You may see some examples here.
Women-specific mummy bag:
- In this case, you typically have more insulation in the foot area and around the chest.
- Typically smaller and more lightweight as expected.
Mummy sleeping bags without zippers
This is a new design, used in 2-season sleeping bags. Instead of zippers (which add weight), you have a large opening on the top accompanied by a ‘comforter’ which you use as a kind of blanket in this opening. You can see a nice example of that bag in the case of Sierra Designs Cloud 800 sleeping bag.
Mummy sleeping bags with an integrated sleeping pad
The idea behind this design is to save weight and to improve insulation. The weight is saved in the following way:
- The bottom part of this sleeping pad, i.e., the one in the contact with the ground is in fact just a fabric without insulation. The fill in the bag, in general, loses its insulation properties when it is pressed by your body, so having the fill in this lower area may be pointless.
- So instead of the bag fill beneath you, you will have a sleeping pad that is naturally designed to be pressed by your body. So the insulation from the ground is still good enough and you have a more lightweight bag.
The bags of this type have a sleeve where you can put the sleeping pad so that it does not move. See a nice example in this Big Agnes Lost Dog series.
So in general, if you want to be warm and lightweight mummy-type is your sleeping bag. But make sure that it is a proper size to have an optimal thermal efficiency; it should not be too snug.
Regarding the temperature rating please have a look into my another text on this issue.
This is a type that shares some features with both other types. General features:
- A bit tapered in the foot area.
- With a hood, and without a hood.
- The zipper can go all the way around the foot area, so it can be used as a blanket as well.
A few tips on how to handle your sleeping bag:
- You do not want to roll it before putting it into your bottom compartment of the pack or into its bag. Stuff it instead, this way you will put it in with less air trapped inside.
- Start stuffing from the foot area because this is where the air will be trapped and the fill is usually thicker.
Here is a very short video where the three basic types of sleeping bags are presented, please have a look:
In this text, I have tried to answer the question about what a mummy sleeping bag is. I gave a few examples which are currently available on the market, so just follow the links for more details. I hope the text was useful to you, please feel free to share it with others.
Thank you for reading and please leave some comment in the box below.