There are a multitude of reasons to get a sleeping bag liner—from adding some warmth (up to 25 degrees!) to your sleeping bag to avoiding dirty travel linens. Bringing a sleeping bag liner on the trail is incredibly useful for keeping your sleeping bag cleaner, as sleeping bags are often more difficult to launder than the liner will be. Sleeping bag liners can also be a great option for travelers, as a rectangular bag liner can be used instead of thick sheets on summer nights. Here's a breakdown of some components of liners that can help you pick the best option for your lifestyle!

Why Use a Sleeping Bag Liner?

A sleeping bag liner traditionally fits inside your sleeping bag to help keep your sleeping bag cleaner and protected from dirt on the trail, especially when you’re muddy and dusty after a long day of hiking.

Temperatures change drastically and sporadically in the mountains. For less than a pound of weight, a liner is a worthy addition to your pack. If temperatures drop, you have extra warmth. If temperatures rise, ditch the sleeping bag and use the liner instead. Bringing a liner with you on your next trip will help you to be prepared for any situation.

You can also think of sleeping bag liners as an alternative to travel sheets (no thank you, bed bugs!) which will be larger and heavier than a liner. A rectangular liner is also great for car camping on summer nights when you want to save space in your car for other gear.

Shape

Sleeping bag liners come in two shapes: rectangular and mummy.

Rectangular

A rectangular sleeping bag liner is a great choice for travelers wanting to avoid bedding with questionable cleanliness levels or for summer car camping trips, road trips, and even backpacking with a rectangular sleeping bag (although I recommend a mummy shape for backpacking instead). It is recommended, and sometimes required, to bring one to hostels for your nights.

Mummy

A mummy sleeping bag liner is lighter in weight and more compact than a rectangular liner. Therefore, it’s better for weight-saving travels such as backpacking or bikepacking. They come in a variety of materials and can add a range of 5 to 25 degrees of extra warmth to your sleeping bag. For those who have a 3-season sleeping bag and do not want to spend the money on a winter bag, a liner can help to bridge the gap and is far less expensive.

Material

Silk

Silk is very lightweight (often 4-6 ounces) and packs down extremely small. Silk is known for insulating in cooler conditions but will still be breathable in warm weather. A silk liner is on the more expensive end of sleeping bag liners, but I think the softness of silk and the weight to warmth ratio make it worth the extra dollars!

Cotton

Cotton is a durable, heavy, and absorbent material. While it is cheaper than most sleeping bag liners, it’s also heavier and less compact. It will definitely add bulk to your backpack. Cotton is not recommended to bring on the trail since it takes longer to dry than synthetic materials. The slow dry time makes it dangerous to use in colder conditions because if you happen to get water or sweat on the fabric, it won’t keep you warm. But if you are simply buying a liner for hostel accommodations on your trip around Europe, then this would be a very economical choice.

Another option for hostel accommodations is the built-in bug protection that Sea to Summit offers with their Shield protection technology. Think insect shield in a blanket! Say goodbye to the pesky mosquitoes!

Fleece

Fleece and microfleece can add up to 15 degrees of warmth depending on the manufacturer. These materials are soft to the skin, quick-drying and moisture-wicking, and heavier than other options. They are often far bulkier but not as expensive as other fabrics.

Synthetics

Synthetics (i.e. CoolMax) are great for humid conditions due to their moisture-wicking and breathable properties. Synthetics are a bit more relaxed and have some stretch to them, which is great if you are constantly kicking around in your sleeping bag to get comfortable.

Insulated Liners

Insulated sleeping bag liners are said to add up to 25 degrees of warmth to your sleeping bag. These are often more expensive but tend to be worth it for the hollow-core fiber insulation that helps the material dry at twice the speed of cotton. These are great if you plan on pairing your liner with your 3-season sleeping bag in colder conditions if you’re not quite sure if you need a warmer sleeping bag or even like winter camping!

My Picks

Sea to Summit Reactor Extreme Liner

For colder conditions, check out the Sea to Summit Reactor Extreme Liner that adds 25 degrees of warmth to your sleeping bag. It comes with a stuff sack and uses a thermolite polyester fabric to keep you comfortable when the temperatures drop. Its mummy shape pairs nicely with any mummy bag you have and weighs only 14 ounces which will only add 0.8 lbs to your pack—a worthy addition to any winter backpacking adventure. Being cold flat out sucks! It is the worst, especially when you are trying to sleep. Bring the liner to help avoid any feelings of “I hate camping in winter.”

Sea to Summit Adaptor CoolMax Liner

For humid temperatures in buggy environments, grab yourself a Sea to Summit Adaptor CoolMax Liner. This is an excellent choice that is incredibly stretchy and soft on the skin. It helps to wick moisture away from your skin, allowing it to leave your body and keep you comfortable. Pair this with a bag or use it as a stand alone option. It comes with an Insect Shield that will add protection in buggy environments and keep those annoying ticks out of your skin. It’s made with CoolMax polyester fabric and weighs just under 9 ounces.

Cocoon Microfiber Mummy Liner

The best sleeping bag liner on a budget is the Cocoon Microfiber Mummy Liner. This is a simple bag that will be great on your skin and add 5 degrees of warmth to your sleeping bag. That really won’t help in colder temperatures, but for those just wanting to keep their bag clean, this will do the trick. It packs down smaller than a water bottle and weighs 8 ounces. It’s also machine washable and very breathable. It will feel great on your skin after a long day on the trail exploring!

Sleeping bag liners aren’t for everyone. I find some can make me feel claustrophobic inside my sleeping bag and I won’t get a good night's sleep. But some adventurers find them necessary to enjoy the great outdoors and stay safe. Regardless, they can be extremely useful and can add an extra layer of protection and safety from the elements.

Do you prefer camping with or without a sleeping bag liner? Did your favorite liner make the list or are you looking for another option? Hit up a Camping & Hiking Expert here on Curated to chat more about it!