A guide to the best ultralight sleeping bag liners for backpacking and hiking.
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.
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.
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.
Washable. 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.
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.
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.
Not all sleeping bag liners are created equal. Here are some differentiating factors.
Materials: There are several types of liner materials: cotton, silk, fleece, merino wool and polyester 'blends' are the most common. Cotton is my personal favorite simply because of the way it feels on my skin. Slightly heavier 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, except for its hefty price tag. Blends range all over the map on materials.
Heat Rating: 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.
Weight: 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.
Tapered or Rectangular: You can get liners that are rectangularly shaped (more spacious to sleep in) or tapered around the head and feet (lighter and more compact). Some also come with an adjustable drawstring around the head to "mummy" it around your face.
Bug Protection: If you like to cowboy camp (no tent) a lot, 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.
Breathability: 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.
This is the sleeping bag liner I personally use. It is not the warmest. But, I'm a sucker for the way this cotton/polyester material feels. Insect Shield is built in as an invisible and odorless bug protectant.
Weight: 8.6 oz; Warmth: 5° F
Very comfortable material and similar to the Sea to Summit liner above... except the Cocoon Coolmax costs about $15 less. You sacrifice the Insect Shield though.
Weight: 9.0 oz; Warmth: 5° F
The definition of an ultralight liner. These weigh less than half of most sleeping bag liners. Sleek silk material packs down tiny and feels great on the skin. Costs about $20 more than most other liners.
Weight: 3.6 oz; Warmth: 5° F
Great warmth-to-weight ratio. This liner can stand as a light blanket on its own and is great for colder backpacking conditions. A little bulky. Also check out the Reactor PLUS model for even more warmth.
Weight: 8.1 oz; Warmth: 15° F
A very popular silk bag liner. It is less expensive than the Western Mountaineering Tioga. It weighs over an ounce more though.
Weight: 4.7 oz; Warmth: 5° F
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.
By Chris Cage
Chris launched Greenbelly Meals in 2014 after thru-hiking the Appalachian Trail for 6 months. Since then, Greenbelly has been written up by everyone from Backpacker Magazine to Fast Company. He wrote How to Hike the Appalachian Trail and currently works from his laptop all over the globe. Instagram: @chrisrcage.
650-calorie fuel. No cooking. No cleaning.