A mummy sleeping bag is a self-contained sleeping bag that has a hood that covers the whole head, fits closely around the shoulders, and narrows towards your feet. This shape allows the sleeping bag to hug closely to the body and wrap around the head.

outdoor camping cold weather sleeping bag

Why Choose a Mummy Bag?

A mummy bag can be an excellent choice whether backpacking or glamping. Mummy bags have several advantages and disadvantages over traditional rectangle sleeping bags.

If you’re backpacking, you should usually choose a mummy bag. Mummy bags are smaller, making them lighter, and a more packable design. In addition to weight and size, it’s also a warmer option.

Rectangle sleeping bags are often too bulky and heavy for backpacking. This bulk is usually due to wasted space inside the bag, causing a significant loss in heat retention.

Mummy bags are the best choice for the winter. Depending on brand and temperature rating, they are usually much more efficient than rectangle sleeping bags.

If you know that temperatures are going to be extremely low, you can add a sleeping bag liner.  This liner is the same shape as the mummy bag and adds up to 25 degrees Fahrenheit of warmth to your sleeping bag.

These sleeping bag liners can also be used as a sleeping bag alone in warmer months. This liner will block minor breezes and keep you from getting chilled. Sleeping bag liners pack down very small and light, so this is an excellent option for minimalist summer camping.

Pros of a Mummy Bag

•    Warmer:

Mummy bags are designed to somewhat form around the body. They fit loosely around the shoulders and taper down at the feet. These sleeping bags also have a hood that wraps around the head.

Mummy bags also typically have a drawstring around the hood similar to a winter jacket. This drawstring allows you to close the hood most of the way for maximum heat retention.

The snug fit is what makes mummy bags so much warmer than a standard rectangle bag.

•    Lighter weight:

As with other camping gear, weight depends on the material that you choose. Depending on the brand and fill material, mummy bags weigh less than other sleeping bags. This difference in weight is mostly due to the size and amount of materials used to make the sleeping bag.

Weight is essential when choosing a sleeping bag. When you’re glamping, weight doesn’t matter so much. Weight is much more critical when backpacking. Try to stick to under or around two pounds when choosing a sleeping bag for backpacking.

•    Packable:

When comparing to a standard rectangle bag, mummy bags are much more compressible. Ability to pack down the sleeping bag partially depends on what insulation you choose, but the shape is what allows mummy bags to pack down much smaller.

Mummy bags have a more rounded shape, and there are no corners on the sleeping bag. This design allows you to fold and roll the sleeping bag in the same way that you would a rectangle bag. You can also compress a mummy bag into a stuff-sack to save even more space.

Cons of a Mummy Bag

•    Less room:

As we know the pro is that the mummy bag hugs the body to allow better heat retention, there’s also a negative to that.

When sleeping in a mummy bag, there’s usually not much room to move around. Although this may not be an issue for some, some people get a little claustrophobic.

•    Usually just for one person:

While this isn’t always the case, mummy bags are almost always for one person. The don’t zip together or unzip to fold out like a quilt.

There are, however, specific mummy bags that can be zipped together. This design allows you to make a two-person mummy bag. Although the option is out there, two bags zipped together may sacrifice warmth.

Which Mummy Bag is Best?

The best mummy bag for your adventures has a lot of variables. The first one would be insulation.

If you’re planning a trip in which temperatures are going to be very cold, a down sleeping bag is going to be one of your best options. Duck or Goose down is one of the best natural insulators.

Down sleeping bags will be the most compressible, and the warmest sleeping bag. Quality down can be one of the most expensive insulators in sleeping bags.

Sleeping bags insulated with down will hold their compression longer than any other insulation. Compress them hundreds of times, and they will retain that fluffy warmth we all love.

The only issue with down sleeping bags is that they can’t get wet. Down insulation clumps together and loses its insulating capabilities when it gets wet. Down must also be appropriately cared for in order to retain its insulating properties.

Always be sure to read any, and all of the care instructions after you purchase a down sleeping bag. Proper care is critical to the lifespan of your sleeping bag.

If you’re planning a trip that you know you may get wet, consider a synthetic fill sleeping bag. Although it still won’t be as warm, synthetic down tends to retain at least 25% of its insulating properties when it gets wet.

Synthetic insulation won’t last as long and will begin to lose its fluff sooner than down. If you’re on a budget, synthetic-filled sleeping bags are a bit more affordable.

Always consider the weight of a sleeping bag if you’re purchasing it for backpacking. Down will be lightest, and synthetic will be the next-to-lightest. Around two pounds is an excellent weight for backpacking sleeping bags.

When a Mummy Bag is the Best Choice

Due to the weight and compressibility, mummy sleeping bags are best for backpacking. Remember, everything you take has to be carried on your back.

If you’ve ever gone backpacking with a sleeping bag that was too big and too heavy, you know exactly why weight and size are so critical.

Another excellent time to have a mummy sleeping bag is when temperatures are going to be very low. This situation applies for all camping, whether backpacking or in an RV without heat.

In addition to the added warmth of a mummy bag, sometimes you’ll need a little extra insulation. Sleeping bag liners help, but depending on geographic location, it’s sometimes still hard to stay warm.

Additional Warmth for Your Mummy Bag

Wearing proper clothing can contribute to staying warm when you sleep in your mummy bag. Merino wool clothing is an excellent insulator that is both warm, and quick dry if you get overheated.

Patagonia, SmartWool, and Icebreaker all make excellent base layers that will keep you warm inside your mummy bag.

Socks and gloves will also help in very extreme temperatures. We all know how cold toes can get in the wintertime.

Merino Wool socks, such as SmartWool or Darn Tough socks are some of the best on the market.

Outdoor Research offers many styles of gloves that are made from wool or Merino Wool. Fingers and toes are typically the first part of the body to get frostbite when the temperatures are low enough.

In addition to dressing properly in low temperatures, a ground pad should also be used. Ground pads will keep you more comfortable through the night.

Not only do ground pads provide a more cushioned surface to sleep on, but they also aid in insulating the side of you that’s on the ground.

As you lay on your sleeping bag, it compresses, which makes that side lose its loft. When this happens, the insulation won’t perform as well as it should.

Ground pads are available in a wide variety of options including foam, inflatable, and self-inflatable.

Biggest Advantages of Mummy Bags

All in all, the most significant advantage of a mummy bag is warmth. When compared to traditional rectangle sleeping bags, mummy bags are a sure win.

The second advantage is packability and weight. There’s no easier sleeping bag to manage on the trail quite like a mummy bag. It’s light, packable, and if you choose down, it has an average lifespan of over ten years depending on use.

When choosing a mummy sleeping bag, always compare weight, insulation rating, and size. Consider the conditions you’ll be using it in, as well. There are many situations that down is a no-so-great option, such as rainy winter backpacking.

On the other hand, down is the best choice for dry winter backpacking. As you can see every situation is different and planning ahead will help you plan the best and safest trip possible.

If you choose down, always look at the fill-power rating. The higher the rating number, the higher quality the insulation will be.

When choosing insulation, check the temperature rating. The temperature rating will give you a general idea of how warm the sleeping bag will be.

If possible, always aim to get a sleeping bag with a lower temperature rating than you’ll need. It’s easier to un-layer than to be cold and not have brought extra layers.