What is a sleeping bag liner—or as we call our liners, TravelSheets and MummyLiners? It sounds simple enough. A liner for your sleeping bag, right? While that is true, there’s a lot more to this multi-functional piece of gear and travel accessory than an additional layer or sheet for sleeping bags.

You’ll come across a few different categories to choose from when shopping for sleeping bag liners. Like purchasing bedsheets, choose the liner that fits the size and shape of your sleeping bag.

Mummy-shaped liners

Mummy-shaped sleeping bag liners, or MummyLiners, are shaped to maximize body heat retention and fit snugly into mummy bags. Mummy liners are often equipped with a drawstring opening at the top to maximize insulation.

Rectangle liners

Rectangle sleeping bag liners fit traditional rectangular-shaped sleeping bags. They often have a small opening towards the top of the liner for easy entry with a zipper or velcro closure. COCOON^® rectangle liners are called TravelSheets. Alongside fitting comfortably into rectangular sleeping bags, they also stand alone as sheets for travel or as warm-weather sleeping bags. 

Dual liners

Dual liners fit two people. They work great as double or queen-size bed sheets for travel and fit into rectangle-shaped double sleeping bags

Even if you’re not someone who travels, backpacks, or bikepacks, there are benefits to keeping a sleeping bag liner in your home as well. Read on to find out why using a sleeping bag liner at home is beneficial for hygiene and cleanliness.

Sleeping bag liners make your sleeping bag warmer

And the ability to add insulation to your sleeping bag is a big deal! Especially on those evenings when the temps dip lower than anticipated. It’s always best to be well-prepared.

Every sleeping bag has lab-tested comfort and limit ratings (noted as “EN” for European Norm or “ISO” for International Standard Organization ratings). Typically, women’s sleeping bags are labeled based on their comfort rating. This indicates the minimum temperature at which a cold sleeper might be able to maintain a comfortable sleep temperature within the sleeping bag.

Men's sleeping bags, on the other hand, often feature the “lower limit rating”. This rating indicates a temperature below the comfort rating. It denotes the minimal temperature at which a warm sleeper might maintain comfort within the sleeping bag.

Whichever insulation rating your sleeping bag uses, a sleeping bag liner will improve its effectiveness. Some sleeping bag liners can even increase the insulation rating of a sleeping bag by 25-45 degrees Fahrenheit! That’s a huge deal when you’re out backpacking or in a cold environment. And at the cost of as little as a few hundred extra grams in your pack, sleeping bag liners are a pivotal piece of gear for backpacking, bikepacking, and camping.

Stay dry, stay comfortable, stay out longer

Many sleeping bag liners and travel sheets are made out of moisture-wicking materials like silk, COOLMAX^®  technology, and microfleece. These materials are both breathable and also wick water and sweat away from the skin. This helps to keep you warm, dry, and comfortable all night long whether you’re facing condensation in a cold tent or your own sweat beading up while you sleep.

Sleeping bag liners protect your sleeping bag from. . . You!

Sleeping bags can be a hefty investment. You probably want yours to last as long as possible. If this is the case, a liner is a must.

Sunscreen, bug spray, body oil, dirt, and even scents (think food and campfire smells) that build up in your hair, skin, and clothing accumulate in your sleeping bag. Minimally, a smelly sleeping bag can be an annoyance and cause the sleeping bag to require more frequent washes. This increases the risk of tears and displaced filling (for more information on this, visit our previous post on how to wash sleeping bags properly. At worst, a smelly sleeping bag can attract bears and other unwelcome critters to your campsite.

Sleeping bag liners add a layer of protection between your pricey, comfy sleeping bag and whatever is on your skin, clothes, or hair. Body oil and other, less natural, oils on your skin (like sunblock and bug spray) can cause your sleeping bag's filler to clump over time. As a result, the loft, insulation rating, comfort, and overall lifespan of your sleeping bag will suffer.

Huts, hostels, and hotels

I don't think anyone needs to be told twice that hostel and hotel sheets can be downright unhygienic. In fact, many huts and hostels do not provide bedsheets at all and require that you B.Y.O. travel sheet or bedding. Whenever you’re sleeping where many other bodies have slept before, bringing your own travel sheets offers a nice peace of mind.

A travel sheet with a pillow insert can protect you and your pillow from body oils, dead skin, bacteria, and even bed bugs that can be found on bedding in hostels, huts, and even hotels.

Use travel sheets to keep a hygienic home

Travel sheets are useful on the go and at home. When the holidays roll around and all your family comes into town, you know someone is going to end up sleeping on your nice new couch. If the Covid-19 pandemic taught us anything, it’s the importance of personal hygiene. Keeping extra travel sheets in your home is the perfect way to keep your space clean and hygienic when you have house guests.

Giving each guest their own travel sheet to use, protects your furniture from harboring bacteria and viruses and reduces spot cleaning due to sweat, drool, hair, and body oil. Most travel sheets can be machine washed and dried quickly either in a dryer or by hang drying. It’s much easier to wash travel sheets than to clean and disinfect furniture.

Bonus points: You’ll look like a thoughtful and well-prepared host with a personal travel sheet for each guest!

With so many different kinds of travel sheets and sleeping bag liners available, it can be overwhelming to choose the right one. Different materials better suit different climates, weight considerations, and sleeper preferences. But with so many options available, you can absolutely find the sleeping bag liner that feels as cozy as your own bed no matter where in the world you find yourself.

This quick and simple guide to choosing the right sleeping bag liner will help you make the right choice for your needs.

Silk sleeping bag liners

• Lightweight and compact. Great for backpacking, carry-on luggage, and packing light.
• Offers added insulation for cold weather.
• Also a great warm-weather option due to its impressive breathability.
• Moisture-wicking and facilitates quick evaporation of sweat, condensation, and other moisture buildups.
• Silky smooth, comfortable, and luxurious.

Fleece, microfleece, and merino wool sleeping bag liners

• A bit hefty but offers great insulation.
• Quick drying options that offer efficient moisture-wicking properties.
• As far as natural materials go, wool is considered the gold standard for staying warm and dry.
• Not the best option when luggage or pack space is limited or when reducing weight is a priority.

Cotton

• One of the most economically friendly options.
• Good for both cooler and warm climates.
• Incredibly durable which makes cotton travel sheets great for hostel hopping and long stints on the road.
• More compact than fleece and microfleece but less compact than silk.
• Comfortable and cozy.
• Absorbant (but not as efficient of moisture-wicking properties as some other options). Creates a natural vapor balance.

Thermolite^® One of the most economically friendly options

• The warmest option in the COCOON®  line of TravelSheets and MummyLiners. Great for shoulder season and winter backpacking and camping.
• Thermolite®  EcoMade dries 20% faster than other insulating fabrics and 50% faster than cotton.
• Wicks moisture to the surface of the fabric for quick evaporation.
• Lightweight and compact.

COOLMAX^®

• Great for warm, humid environments. Makes a great sleeping bag or bedsheet when traveling through the tropics and similar climates.
• Breathable with supreme moisture-wicking performance.
• Lightweight and compact.
• Fastest drying moisture-management fabric.

With 19 varieties of TravelSheets and MummyLiners, COCOON^® offers one of the most expansive lineups on the market. TravelSheets are our flagship product and have been refined and perfected over decades to provide travelers like you with the most comfortable and reliable sleep systems for traveling, backpacking, bikepacking, and camping.