A sleeping bag liner does exactly what it sounds like - it lines your sleeping bag. The liner is usually made of a thin cloth and is shaped like a cocoon. It is designed to be worn as a barrier between you and the actual sleeping bag itself. You can sleep in the liner wearing clothes or butt naked. Think of a sleeping bag liner as a bed sheet for the backcountry.
At a Glance:
‣ Sleeping bag liners protect the inside of sleeping bags from dirt and oils.
‣ Liners have many benefits: they provide additional warmth, can be used alone in warmer climates, and prevent you from having to wash your sleeping bag too often.
‣ Consider weight, shape, and fabric (cotton, silk, polyester blends, etc.) when choosing.
‣ Best models by Sea to Summit, Cocoon, Western Mountaineering, and more.
Not all sleeping bag liners are created equal. Here are some differentiating factors.
MATERIALS: COTTON VS. SILK VS. FLEECE VS. WOOL
There are several types of liner materials: cotton, silk, fleece, merino wool and polyester 'blends' are the most common. Blends range all over the map on materials.
- Cotton's main advantage is that it feels great on the skin. It is slightly heavier than other fabrics, though, and worthless when wet.
- Silk is ultra lightweight and very comfortable, but less durable.
- Fleece is cheap and warm, but heavy and bulky.
- Merino wool is the best for weight, warmth and comfort. But, it carries a hefty price tag.
Silk sleeping bag liner (Cocoon Silk Mummy)
HEAT RATING: UP TO 25 DEGREES
Most companies will provide some sort of temperature rating in the specs. This number is only the additional amount of warmth it can provide. The warmest backpacking liners are rated up to 15-25 degrees. A warm liner will provide extra warmth in the winter and can be used as a stand-alone sleeping bag in warmer months.
Big Agnes Sleeping Bag Liner
WEIGHT: NOTHING OVER A POUND
Obviously, a 25 degree thermal liner will weigh more than a 5 degree sheet. Consider how much of a priority the thermal properties are to you before getting a heavy liner. Even the thickest liners should not weigh more than a pound though. The lightest model on our list is the Western Mountaineering Tioga which only weighs 3.6 ounces
Packed Cocoon Sleeping Bag Liner
SHAPE: TAPERED OR RECTANGULAR
You can get liners that are rectangularly shaped or tapered around the head and feet. The former is more spacious to sleep in, while the latter is lighter and more compact. Some sleeping bag liners also come with an adjustable drawstring around the head to "mummy" it around your face.
Big Agnes opens on the side for easy entry and exit
BUG PROTECTION: BEST FOR COWBOY CAMPING
If you like to cowboy camp (ie. no tent), bugs crawling at night on and around you can be an issue. Some liners come with insect resistant coated fabrics to deter any the unwanted creepy crawlies. If you sleep inside your tent, this feature won't be as necessary.
Sea to Summit Coolmax Insect Shield information w/ cordlock
BREATHABILITY: LOOK FOR COOLMAX LINERS
Sleeping bags can get steamy. You want your liner to help wick any moisture away from your body. Not crucial, but look for liners with the "CoolMax" trademarked feature if you tend to sweat. CoolMax is a cooling technology that moves moisture away from your body and allows it to evaporate from the fabric quickly. Note that merino wool is another fabric that has fantastic moisture-wicking properties.
The Best Sleeping Bag Liners
|Brand & Model||Weight||Material||Price|
|SEA TO SUMMIT - REACTOR THERMOLITE||8.7 oz||Polyester||$63|
|WESTERN MOUNTAINEERING - TIOGA||3.6 oz||Silk||$80|
|COCOON - SILK MUMMY||4.4 oz||Silk||$60|
|SEA TO SUMMIT - INSECT SHIELD COOLMAX||8.7 oz||Polyester||$63|
|COCOON - COOLMAX||9.0 oz||Polyester||$46|
|ALPS MOUNTAINEERING MICROFIBER MUMMY||11 oz||Polyester||$25|
|BIG AGNES SLEEPING BAG LINER - COTTON||14.5 oz||Cotton||$45|
|THERM-A-REST SLEEP LINER||11 oz||Polyester||$60|
SEA TO SUMMIT - REACTOR THERMOLITE
- Weight: 8.7 oz
- Material: Thermolite Polyester
- Price: $63
- Why we like it: Adds a significant amount of warmth and comfort to your bag for less of a weight penalty than many other liners.
This liner provides a great warmth-to-weight ratio. In fact, this is one of the warmest sleeping bag liners available. And, it weighs less than many comparable liners. This can stand as a light blanket on its own. And, it is great for colder backpacking conditions when you need to add serious warmth to your sleep system. Although, it is a little bulky. Also, check out the Reactor PLUS model for even more warmth.
WESTERN MOUNTAINEERING - TIOGA
- Weight: 3.6 oz
- Material: 100% Silk
- Price: $80
- Why we like it: Lightest sleeping bag liner we’ve tried, and the silk is ultra-soft and cozy, making it the perfect addition to an ultralight sleep system.
This is the definition of an ultralight sleeping bag liner. This weighs less than half of most liners but provides just as much comfort and warmth as the heavier liners out there. The sleek silk material packs down tiny and feels great on the skin. It is one of the more expensive liners out there. But, at 3.6 oz this a great value for ultralight backpackers.
COCOON - SILK MUMMY
- Weight: 4.4 oz
- Material: Silk
- Price: $60
- Why we like it: Less expensive silk liner. Adds a smooth, odor-resistant layer between you and your sleeping bag for not much of a weight penalty.
This is a very popular silk bag liner and a great choice for ultralight backpacking. Like other ultralight liners, it is pretty basic, but this liner excels in its simplicity. The silk is soft on the skin and doesn’t hold odors as much as other materials, too. It is less expensive than the Western Mountaineering Tioga. However, it weighs over an ounce more than that liner. If you’re looking for a less expensive silk liner, this is a great option.
SEA TO SUMMIT - INSECT SHIELD COOLMAX
- Weight: 8.7 oz
- Material: CoolMax Polyester
- Price: $63
- Why we like it: Soft and plush sleeping bag liner that is great for summer camping. It keeps bugs from crawling on you when you aren’t sleeping in a tent.
This sleeping bag liner is a personal favorite of many experienced backpackers. It is not the warmest, but it is so comfortable you will find the low warmth-to-weight ratio worth carrying. The Insect Shield provides invisible and odorless bug protection. So, if you like to sleep out under the stars, this is a great option for a sleeping bag liner.
COCOON - COOLMAX
- Weight: 9.0 oz
- Material: CoolMax Polyester
- Price: $46
- Why we like it: It keeps you cool and dry in hot weather when used on its own, and it works great as a layer between you and your sleeping bag when the temperatures drop.
This liner is made of a very comfortable material similar to the Sea to Summit liner above. Except, the Cocoon Coolmax costs about $15 less. You do sacrifice the Insect Shield, though. If you’re a warm sleeper, you should look for a liner that breathes well and wicks away sweat. This liner is a great option if you meet that criteria.
ALPS MOUNTAINEERING MICROFIBER MUMMY
- Weight: 11 oz
- Material: Polyester
- Price: $25
- Why we like it: Very inexpensive option for someone looking to try a sleeping bag liner for the first time.
This liner is made of synthetic microfiber material that will feel cozy like a fleece blanket next to your skin, especially after washing it a few times. Unlike most liners that you have to crawl into from the top, this liner folds open on the right side. This makes getting in and out of it much easier. For this reason, it will feel more like your sheets at home, too. However, if your sleeping bag opens on the left side this right side opening can be a little awkward. Also, check out the poly-cotton version.
BIG AGNES SLEEPING BAG LINER - COTTON
- Weight: 14.5 oz
- Material: 100% Cotton
- Price: $45
- Why we like it: Great to throw in your travel bag to provide a soft layer between you and whatever you end up sleeping on.
This liner is 100% cotton, so it is great for summer trips where you’re looking for comfort more than warmth. This is one of the heavier liners in this review, so it’s not really suited for backpacking, except in hot weather where you can use this instead of a bag. This liner opens on the side and snaps shut so you can easily control how much coverage you’ll have, too. And if the side opening on this liner isn’t on the same side as your bag, just flip it inside out and it will be.
THERM-A-REST SLEEP LINER
- Weight: 11 oz
- Material: Brushed Embossed Polyester
- Price: $60
- Why we like it: Very easy to get in and out of with the side entry zipper. The zipper gives versatility when camping in warm weather since you can use it to ventilate.
With a ¾ length side entry zipper, this liner is very easy to get into. Also, if it gets a little warm during the night you can unzip the liner to give more ventilation. The brushed polyester material is soft on the skin, so you’ll feel cozy no matter where you lay down for the night. This liner will work best with quilts or sleeping bags with a left-side zipper since that is where the liner’s zipper is located.
Only got $10 for a liner, huh? Cool. You can always make your own. You will need some needle and thread and a few hours to spare as well. Find a fleece blanket or bedsheet at Walmart. Follow instructions on how to shape and sew your own here.
What Is the Point of a Sleeping Bag Liner?1. Additional Warmth
Depending on the thickness, a sleeping liner can help insulate a lot of extra precious heat inside your sleeping bag. Example: a sleeping bag rated at 30 degrees, with the addition of a 10 degree liner, could then be rated at 20 degrees.
2. Seasonal Flexibility
A sleeping bag liner is not only great extra warmth in cold weather, but it's also great for warm weather. Instead of packing your heavy and bulky sleeping bag around with you that will be a sweaty oven, you might be able to only pack your liner. They are very lightweight and most can pack down enough to fit inside a Nalgene bottle.
It is a huge pain to wash a sleeping bag. It can be especially painful washing a down sleeping bag. The dry cleaners are super expensive and time consuming. Some cleaners may not know how to treat a down bag and can destroy it's loft and insulation ability. On the contrary, sleeping bag liners are easily washable at home and can save you a trip to the cleaners.
4. Sleeping Bag Protection
On the cleanliness note, by wearing a liner at night, you will inevitably minimize the amount of dirt, oil and filthy hiker grime that reaches your sleeping bag. Protecting a $500 bag with a $50 liner makes a lot of sense.
5. Super Comfortable
Most backpacking clothing is synthetic. Most sleeping bag material is synthetic. Most hikers long for the feel of bed sheets at the end of a long day. A soft liner to cuddle up inside is the next best thing.
How to wash a sleeping bag liner?
Most liners can be machine washed on a gentle cycle with classic laundry detergent. It's preferable to air dry the liner and not use any fabric softener. If you're using a top loading machine, SeatoSummit recommended stuffing the liner in a pillow case to avoid any straps from getting caught in the impeller.
How do you waterproof a sleeping bag liner?
Sleeping bag liners aren't waterproof. If, for some reason, you needed yours to be, you could you wanted to protect, you could simply use waterproofing spray to add a layer of protection after you wash it. After applying the spray, let the fabric dry for at least 48 hours before you pack or use your liner.
📸 Some photos in this post were taken by Jonathan Davis (@meowhikes)